[Pseudo Probe] Use the name from debug info to compute GUID in probe desc

This is to fix a GUID mismatch while decoding pseudo probe, a GUID from the inline tree is not in the GUID2FuncDescMap. It turned out that frontend could change the function name making it different from the one in debug info(https://reviews.llvm.org/D111009). Here change to use the function name from debug info to be consistent with the probe name from the inline stack.

Reviewed By: hoy, wenlei

Differential Revision: https://reviews.llvm.org/D146657