Focus disabled optimizations on just BGRAConvolve2D, and only 32-bit.

gyp/core.gyp

 # Core Skia library code.
 {
   'targets': [
     {
       'target_name': 'core',
       'product_name': 'skia_core',
       'type': 'static_library',
       'standalone_static_library': 1,
       'msvs_guid': 'B7760B5E-BFA8-486B-ACFD-49E3A6DE8E76',
 
@@ skipping 13 matching lines @@
         '../src/sfnt',
         '../src/image',
         '../src/opts',
         '../src/utils',
       ],
       'sources': [
         'core.gypi', # Makes the gypi appear in IDEs (but does not modify the build).
       ],
       'msvs_disabled_warnings': [4244, 4267,4345, 4390, 4554, 4800],
       'conditions': [
-        [ 'skia_arch_type == "x86"', {
-          # GCC autovectorization makes some GMs flaky on 32-bit release builds.
-          # skbug.com/2575.   This bug is likely somewhere here in src/core.
-          'cflags': [ '-fno-tree-vectorize' ]
-        }],
         [ 'skia_os in ["linux", "freebsd", "openbsd", "solaris", "chromeos"]', {
           'link_settings': {
             'libraries': [
               '-lpthread',
             ],
           },
         }],
         [ 'skia_os == "mac"', {
           'include_dirs': [
             '../include/utils/mac',
@@ skipping 73 matching lines @@
           [ 'skia_os == "win"', {
             'include_dirs': [
               'config/win',
             ],
           }],
         ],
       },
     },
   ],
 }