Remove some noisy log messages from showing up in llvm-gsymutil output.

This patch removes two log messages that were causing noisy output:
- when we have a zero sized symbol that gets removed in favor of something with a size or with debug info
- when an inlined function's address range has the same high and low pc, don't emit an error message as this is a common technique to indicate a function has been stripped or is no longer present.

Differential Revision: https://reviews.llvm.org/D156834