Auto merge of #70803 - arlosi:hash-regression, r=eddyb

Fix performance regression in debuginfo file_metadata.

Fixes performance regression caused by #69718.

Finding the `SourceFile` associated with a `FileName` called `get_source_file` on the `SourceMap`, which does a linear search through all files in the `SourceMap`.

This resolves the issue by passing the `SourceFile` in from the caller (which already had it available) instead of the `FileName`

Fixes #70785.