Abort: change the magic value written to NULL

Make sure that the magic value can be cast to a char properly.

BUG=
TEST=


Review URL: https://chromiumcodereview.appspot.com/10541122

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@141814 0039d316-1c4b-4281-b951-d872f2087c98

third_party/tcmalloc/chromium/src/base/abort.cc

@@ -12,7 +12,7 @@ namespace tcmalloc {
 ATTRIBUTE_NOINLINE void Abort() {
   // Make a segmentation fault to force abort. Writing to a specific address
   // so it's easier to find on crash stacks.
-  *(reinterpret_cast<volatile char*>(NULL) + 57) = 0x2001;
+  *(reinterpret_cast<volatile char*>(NULL) + 57) = 0x21;
 }
 
 } // namespace tcmalloc