Rename utf8/utf16 benchmark tests. NFC

- Move the test code out of the benchmark directory.  These were move
  there by mistake in #18258.  Despite their name they are not part of
  `test_benchmark` (and we probably want to keep it that way since they
  are mostly tests TextDecoder which is a browser API).

- Convert benchmark_utf8.cpp from C++ to C.

- Rename tests files to match the names of the tests

- Give the tests consistent names in test_core and test_browser

test/test_browser.py

diff --git a/test/test_browser.py b/test/test_browser.py
index 93c3cce..94a92a8 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -4144,12 +4144,12 @@
     self.run_browser('test.html', '/report_result?0')
 
   @also_with_pthreads
-  def test_utf8_textdecoder(self):
-    self.btest_exit('benchmark/benchmark_utf8.c', 0, cflags=['--embed-file', test_file('utf8_corpus.txt') + '@/utf8_corpus.txt'])
+  def test_utf8_bench(self):
+    self.btest_exit('test_utf8_bench.c', 0, cflags=['--embed-file', test_file('test_utf8_bench.txt') + '@/utf8_corpus.txt'])
 
   @also_with_pthreads
-  def test_utf16_textdecoder(self):
-    self.btest_exit('benchmark/benchmark_utf16.cpp', 0, cflags=['--embed-file', test_file('utf16_corpus.txt') + '@/utf16_corpus.txt', '-sEXPORTED_RUNTIME_METHODS=UTF16ToString,stringToUTF16,lengthBytesUTF16'])
+  def test_utf16_bench(self):
+    self.btest_exit('test_utf16_bench.c', 0, cflags=['--embed-file', test_file('test_utf16_bench.txt') + '@/utf16_corpus.txt', '-sEXPORTED_RUNTIME_METHODS=UTF16ToString,stringToUTF16,lengthBytesUTF16'])
 
   # Tests that it is possible to initialize and render WebGL content in a
   # pthread by using OffscreenCanvas.

test/test_core.py

diff --git a/test/test_core.py b/test/test_core.py
index c795a54..209340c 100644
--- a/test/test_core.py
+++ b/test/test_core.py
@@ -5791,8 +5791,8 @@
   @with_both_text_decoder
   @also_without_bigint
   def test_utf8_bench(self):
-    self.cflags += ['--embed-file', test_file('utf8_corpus.txt') + '@/utf8_corpus.txt']
-    self.do_runf('benchmark/benchmark_utf8.c', 'OK.')
+    self.cflags += ['--embed-file', test_file('test_utf8_bench.txt') + '@/utf8_corpus.txt']
+    self.do_runf('test_utf8_bench.c', 'OK.')
 
   # Test that invalid character in UTF8 does not cause decoding to crash.
   @with_both_text_decoder
@@ -5801,8 +5801,8 @@
     self.do_runf('test_utf8_invalid.c', 'OK.')
 
   def test_utf16_bench(self):
-    self.cflags += ['--embed-file', test_file('utf16_corpus.txt') + '@/utf16_corpus.txt']
-    self.do_runf('benchmark/benchmark_utf16.cpp', 'OK.')
+    self.cflags += ['--embed-file', test_file('test_utf16_bench.txt') + '@/utf16_corpus.txt']
+    self.do_runf('test_utf16_bench.c', 'OK.')
 
   def test_wprintf(self):
     self.do_core_test('test_wprintf.cpp')

test/test_utf16_bench.c

diff --git a/test/benchmark/benchmark_utf16.cpp b/test/test_utf16_bench.c
similarity index 77%
rename from test/benchmark/benchmark_utf16.cpp
rename to test/test_utf16_bench.c
index 8d33d61..0b78b0d 100644
--- a/test/benchmark/benchmark_utf16.cpp
+++ b/test/test_utf16_bench.c
@@ -6,13 +6,13 @@
 #include <stdio.h>
 #include <string.h>
 #include <wchar.h>
-#include <iostream>
-#include <cassert>
+#include <stdio.h>
+#include <assert.h>
 #include <emscripten.h>
 
 EM_JS_DEPS(deps, "$UTF16ToString");
 
-double test(const unsigned short *str) {
+double test(const uint16_t *str) {
   double res = EM_ASM_DOUBLE({
     var t0 = _emscripten_get_now();
     var str = UTF16ToString($0);
@@ -23,17 +23,16 @@
   return res;
 }
 
-unsigned short *utf16_corpus = 0;
+uint16_t *utf16_corpus = 0;
 long utf16_corpus_length = 0;
 
-unsigned short *randomString(int len) {
+uint16_t *randomString(int len) {
   if (!utf16_corpus) {
-//    FILE *handle = fopen("ascii_corpus.txt", "rb");
     FILE *handle = fopen("utf16_corpus.txt", "rb");
     fseek(handle, 0, SEEK_END);
     utf16_corpus_length = ftell(handle)/2;
     assert(utf16_corpus_length > 0);
-    utf16_corpus = new unsigned short[utf16_corpus_length+1];
+    utf16_corpus = malloc(sizeof(uint16_t) * (utf16_corpus_length+1));
     fseek(handle, 0, SEEK_SET);
     fread(utf16_corpus, 2, utf16_corpus_length, handle);
     fclose(handle);
@@ -45,10 +44,10 @@
     if (startIdx + len > utf16_corpus_length) len = utf16_corpus_length - startIdx;
   }
   assert(len > 0);
-  unsigned short *s = new unsigned short[len+1];
+  uint16_t *s = malloc(sizeof(uint16_t) * (len+1));
   memcpy(s, utf16_corpus + startIdx, len*2);
   s[len] = 0;
-  while(((unsigned short)s[len-1] & 0xFF00) == 0xD800) { s[--len] = 0; }
+  while(((uint16_t)s[len-1] & 0xFF00) == 0xD800) { s[--len] = 0; }
   assert(len >= 0);
   return s;
 }
@@ -58,9 +57,9 @@
   double t2 = emscripten_get_now();
   for(int i = 0; i < 10; ++i) {
     // FF Nightly: Already on small strings of 64 bytes in length, TextDecoder trumps in performance.
-    unsigned short *str = randomString(100);
+    uint16_t *str = randomString(100);
     t += test(str);
-    delete [] str;
+    free(str);
   }
   double t3 = emscripten_get_now();
   printf("OK. Time: %f (%f).\n", t, t3-t2);

test/test_utf16_bench.txt

diff --git a/test/utf16_corpus.txt b/test/test_utf16_bench.txt
similarity index 100%
rename from test/utf16_corpus.txt
rename to test/test_utf16_bench.txt
Binary files differ

test/test_utf8_bench.c

diff --git a/test/benchmark/benchmark_utf8.c b/test/test_utf8_bench.c
similarity index 100%
rename from test/benchmark/benchmark_utf8.c
rename to test/test_utf8_bench.c

test/test_utf8_bench.txt

diff --git a/test/utf8_corpus.txt b/test/test_utf8_bench.txt
similarity index 100%
rename from test/utf8_corpus.txt
rename to test/test_utf8_bench.txt