[GTK] Clean up compiler optimizations flags for libWTF, libJSC

https://bugs.webkit.org/show_bug.cgi?id=126157

Reviewed by Gustavo Noronha Silva.

Source/JavaScriptCore: 

* GNUmakefile.am: Remove the -fstrict-aliasing and -O3 compiler flags for libWTF.la. -O3 gets
overridden by -O2 that's listed in CXXFLAGS (or -O0 in case of debug builds) and -fstrict-aliasing
is enabled when -O2 is used (and shouldn't be enabled in debug builds anyway).

Source/WTF: 

* GNUmakefile.am: Remove the -fstrict-aliasing and -O3 compiler flags for libWTF.la. -O3 gets
overridden by -O2 that's listed in CXXFLAGS (or -O0 in case of debug builds) and -fstrict-aliasing
is enabled when -O2 is used (and shouldn't be enabled in debug builds anyway).


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@160996 268f45cc-cd09-0410-ab3c-d52691b4dbfc