Move mips64 target to clang by default.
Move mips64 target to clang by default.

Bug: 23163853
Change-Id: Ia3d449f908b09ce95b3de246c8c699d171dcbaa3

xorware/android_build,xorware/android_build,xorware/android_build,xorware/android_build,xorware/android_build