[llvm] [DWARF] Add option to add linkage_names to call_origin declaration refs (PR #89640)

[Paul T Robinson via llvm-commits]

pogo59 wrote:

> & not sure how this sits with @pogo59's general premise that debugger tuning shouldn't be reachable only through the tuning flags, but should be independently accessible (does independently accessible mean supported in the driver flags, or is -Xclang/cc1/mllvm flags sufficient to meet that requirement?)

What we _don't_ want is
```
if (DD->tuneForLLDB()) {
  doTheLLDBThing();
}
```
Tuning sets the defaults for a bunch of behaviors, but each of the behaviors can be individually controlled outside of the tuning parameter. That is, we could decide to abandon the tuning idea entirely, but still get exactly the same behavior for each target, if we were willing to pass the extra umpteen flags. Whether these are driver, cc1, -mllvm, or whatever, doesn't matter.

https://github.com/llvm/llvm-project/pull/89640