Enable peephole optimizations for aarch64. Also small code refactoring - add PeepholeOpts under Peepholes class. Vladislav Khmelevsky, Advanced Software Technology Lab, Huawei Differential Revision: https://reviews.llvm.org/D118732
Summary: Imported small internal tests: - asm_func_debug.test - basic_instrumentation.test - bolt_icf.test - ctc_and_unreachable.test - double_jump.test - exceptions_args.test - exceptions_instrumentation.test - fptr.test (cherry picked from FBD32032684)