Make OmitFramePointer adjustable for Win/Release build.

build/internal/release_defaults.gypi

 {
   'msvs_settings': {
     'VCCLCompilerTool': {
-      'Optimization': '2',
       'StringPooling': 'true',
-      'OmitFramePointers': 'true',
     },
     'VCLinkerTool': {
       'LinkIncremental': '1',
       'OptimizeReferences': '2',
       'EnableCOMDATFolding': '2',
     },
   },
 }