Better handling of invalid raw exception subcode.

There should be no functional change. If the subcode is invalid it
will continue to default to reason: 'EXCEPTION_STACK_BUFFER_OVERRUN'

Fixing it because some validation tool are complaining of assigning
invalid enum value to a local variable.

Change-Id: I115c46e049517fa261e69b551cfaddb63ea3170a
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/7047357
Reviewed-by: Mark Mentovai <mark@chromium.org>

src/processor/minidump_processor.cc

diff --git a/src/processor/minidump_processor.cc b/src/processor/minidump_processor.cc
index 8387157..0287d6f 100644
--- a/src/processor/minidump_processor.cc
+++ b/src/processor/minidump_processor.cc
@@ -1449,10 +1449,7 @@
           break;
         case MD_EXCEPTION_CODE_WIN_STACK_BUFFER_OVERRUN:
           if (raw_exception->exception_record.number_parameters >= 1) {
-            MDFastFailSubcodeTypeWin subcode =
-                static_cast<MDFastFailSubcodeTypeWin>(
-                    raw_exception->exception_record.exception_information[0]);
-            switch (subcode) {
+            switch (raw_exception->exception_record.exception_information[0]) {
               // Note - we skip the '0'/GS case as it exists for legacy reasons.
               case MD_FAST_FAIL_VTGUARD_CHECK_FAILURE:
                 reason = "FAST_FAIL_VTGUARD_CHECK_FAILURE";