[4.9] workaround for android __cxa_throw_bad_array_new_length bug
Revert "build: set GCC 4.9 as default"

This reverts commit 7cf8b7bb00f288df006d85bf7b2abac5e7c817e6.

There was no measurable gain in any benchmarks I ran from using 4.9, however only degredation due to lowering the
optimization level to Os in skia to get it to run properly (sure it's just one optimization we need to disable for skia
however)