Temporarily adjust Matrix.isSimilarity test tolerance on 64-bit ARM devices

gyp/common_conditions.gypi

 # conditions used in both common.gypi and skia.gyp in chromium
 #
 {
   'defines': [
     'SK_ALLOW_STATIC_GLOBAL_INITIALIZERS=<(skia_static_initializers)',
     'SK_SUPPORT_GPU=<(skia_gpu)',
     'SK_SUPPORT_OPENCL=<(skia_opencl)',
     'SK_FORCE_DISTANCEFIELD_FONTS=<(skia_force_distancefield_fonts)',
   ],
   'conditions' : [
     ['skia_pic', {
      'cflags': [
        '-fPIC',
      ],
      'conditions' : [
       # FIXME: The reason we don't do this on Android is due to the way
       # we build the executables/skia_launcher on Android. See
       # https://codereview.chromium.org/406613003/diff/1/gyp/common_conditions.gypi#newcode455
       ['skia_os != "android"', {
        'target_conditions': [
          [ '_type == "executable"', {
            'cflags': [ '-fPIE' ],
            'ldflags': [ '-pie' ],
          }],
        ],
       }],
      ],
     }],
-    [ 'skia_arch_type == "arm64"', {
-      'cflags': [
-        '-ffp-contract=off',
-      ],
-    }],
 
     # As of M35, Chrome requires SSE2 on x86 (and SSSE3 on Mac).
     [ 'skia_arch_type == "x86"', {
       'cflags': [
         '-msse2',
         '-mfpmath=sse',
       ],
     }],
 
     [ 'skia_os == "win"',
@@ skipping 590 matching lines @@
     [ 'skia_is_bot', {
       'defines': [ 'SK_CRASH_HANDLER' ],
     }],
 
   ], # end 'conditions'
   # The Xcode SYMROOT must be at the root. See build/common.gypi in chromium for more details
   'xcode_settings': {
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }