Add support for counting hotness in compiled code for MIPS

This is a follow up to I0f63c644527b74f6ef2649f481c2a1c731bb9f21.
This fixes 674-hotness-compiled test failures for MIPS32 and MIPS64.

Test: ./testrunner.py --target --optimizing in QEMU
Change-Id: I22eb02594518f315d9e3a3e5fa895a6833574bba