gyp performance: Load detect_host_arch directly.

We ran "python detect_host_arch.py" ~15 times from gyp. Run
detect_host_arch.py directly from from within gyp for faster execution
and since the path is no longer part of the command, the result will
also be cached more often.

The total gain is at best 0.3 seconds. For most people it will be less.

BUG=362075

Review URL: https://codereview.chromium.org/256303003

Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: d2f38924e42a91f762e5cebe5cba1f952c5cefbb
diff --git a/download.py b/download.py
index 2d35c44..6a760df 100755
--- a/download.py
+++ b/download.py
@@ -23,7 +23,7 @@
 BINUTILS_OUT = 'Release'
 
 DETECT_HOST_ARCH = os.path.abspath(os.path.join(
-    BINUTILS_DIR, '../../build/linux/detect_host_arch.py'))
+    BINUTILS_DIR, '../../build/detect_host_arch.py'))
 
 
 def ReadFile(filename):