Auto merge of #54338 - orium:fix-macro-inc-comp, r=nrc
Use full name to identify a macro in a `FileName`.
Before this two macros with same name would be indistinguishable inside a `FileName`. This caused a bug in incremental compilation (see #53097) since two different macros would map out to the same `StableFilemapId`.
Fixes #53097.
r? @nrc