Implement Auto Feedback Directed Optimization Support

Introduces auto feedback directed optimization support for arm,
mips, and x86 targets.

The following should be taken note of:

  - If runtime profile generation (BUILD_FDO_INSTRUMENT) is set,
    auto feedback directed optimizations will be disabled.
    Just as feedback directed optimizations would be disabled.

  - You may prefer to use AutoFDO over FDO by setting BUILD_PREFER_AUTO_FDO

  - If TARGET_FDO_PROFILE_PATH is set, but TARGET_AUTO_FDO_PROFILE_PATH
    is unset, we will attempt to use the FDO profile path instead.
    Otherwise, the default path of
    afdo/profiles/$(TARGET_ARCH)/$(TARGET_ARCH_VARIANT) will be set.
    Note: this will only work if TARGET_FDO_PROFILE_PATH contains afdo runtime
    profiles as well, but is here to cover all bases.

  - LOCAL_NO_AUTO_FDO_SUPPORT may be set to locally disable AFDO cflags, however
    we also abide by LOCAL_NO_FDO_SUPPORT for full compatibility.

  - We will not apply AFDO cflags for host modules by default.

Change-Id: Ia77458b83c6c554c1602912fb5596b522e711ad9

Conflicts:
	core/combo/TARGET_linux-x86.mk