Make static helper methods member functions of OptimizingCompiler class

Make RunOptimizations, MaybeRunInliner and RunArchOptimizations member
functions of OptimizingCompiler class.

Both versions of RunOptimizations are protected in preparation for
bisection bug search CL.

Change-Id: I596efa9ed3fccd1ed3798c6427cc166e2a5d28bd
1 file changed