[BOLT] Add fuzzy function name matching for LLVM LTO

LLVM with LTO can generate function names in the form
func.llvm.<number>, where <number> could vary based on the compilation
environment. As a result, if a profiled binary originated from a
different build than a corresponding binary used for BOLT optimization,
then profiles for such LTO functions will be ignored.

To fix the problem, use "fuzzy" matching with "func.llvm.*" form.

Reviewed By: yota9, Amir

Differential Revision: https://reviews.llvm.org/D124117