Renaming based on suggestion here: 
https://github.com/llvm/llvm-project/pull/139686#discussion_r2089538528

Add support for gsym files to llvm-symbolizer.

co-author @sfc-gh-sgiesecke

Notes:
There was a PR that was 
approved and merged: https://github.com/llvm/llvm-project/pull/134847 
and reverted: https://github.com/llvm/llvm-project/pull/139660
Due to buildbot failures:
https://lab.llvm.org/buildbot/#/builders/66/builds/13851 - it looks like
related
https://lab.llvm.org/buildbot/#/builders/51/builds/16018 - it looks like
related
https://lab.llvm.org/buildbot/#/builders/146/builds/2905 - it looks like
it's not related to changes

Fix:
To fix missing GSYM symbols 
```
+ diff -u expected.new undefined.new
+_ZN4llvm4gsym10GsymReader8openFileENS_9StringRefE U
+_ZN4llvm4gsym10GsymReaderC1EOS1_ U
+_ZN4llvm4gsym10GsymReaderD1Ev U
+_ZN4llvm4gsym13GsymDIContextC1ENSt20__InternalSymbolizer10unique_ptrINS0_10GsymReaderENS2_14default_deleteIS4_EEEE U
+ echo 'Failed: unexpected symbols'
```
for script
compiler-rt/lib/sanitizer_common/symbolizer/scripts/build_symbolizer.sh
LLVMDebugInfoGSYM was added. 
Please check the commit:

https://github.com/llvm/llvm-project/pull/139686/commits/ba55425db9fd8fd1ebb06a4c8d8c95eef213444f
That's the only change compare to
https://github.com/llvm/llvm-project/pull/134847

Reverts llvm/llvm-project#134847

Add support for gsym files to llvm-symbolizer.

co-author @sfc-gh-sgiesecke

---------

Co-authored-by: David Blaikie <dblaikie@gmail.com>

Static analysis found that we could move LineInfo into the Result vector
instead of just copying it.

To reland https://github.com/llvm/llvm-project/pull/124846, we need to
make symbolizer consistent with the case when line number is 0. Always
using filename and line from debug info even if the line number is 0
sounds like the reasonable path to go.

Currently, `DIContext::getLineInfoForAddress` and
`DIContext::getLineInfoForDataAddress` returns empty DILineInfo when the
debug info is missing for the given address. This is not differentiable
with the case when debug info is found for the given address but the
debug info is default value (filename:linenum is <invalid>:0).

This change wraps the return types of `DIContext::getLineInfoForAddress`
and `DIContext::getLineInfoForDataAddress` with `std::optional`.

Identified with misc-include-cleaner.