Remove superfluous PRETTY_FUNCTION define

Source/core/core.gyp

Index: Source/core/core.gyp
diff --git a/Source/core/core.gyp b/Source/core/core.gyp
index 8c47e67fbda2e27e773d4fd74fdca888d6345f0c..4ca980b29f2496e0275add9af53483bdb53a8f46 100644
--- a/Source/core/core.gyp
+++ b/Source/core/core.gyp
@@ -331,9 +331,6 @@
           ],
         }],
         ['OS=="win"', {
-          'defines': [
-            '__PRETTY_FUNCTION__=__FUNCTION__',
-          ],
           # In generated bindings code: 'switch contains default but no case'.
           # Disable c4267 warnings until we fix size_t to int truncations.
           'msvs_disabled_warnings': [ 4065, 4267 ],
@@ -510,13 +507,6 @@
             ],
           },
         }],
-        ['OS=="win"', {
-          'direct_dependent_settings': {
-            'defines': [
-              '__PRETTY_FUNCTION__=__FUNCTION__',
-            ],
-          },
-        }],
         ['OS in ("linux", "android") and "WTF_USE_WEBAUDIO_IPP=1" in feature_defines', {
           'direct_dependent_settings': {
             'cflags': [