The compiler frequently translates TypeScript source file `fileName` strings
into absolute paths, via a `fs.resolve()` operation. This is often done via
the helper function `absoluteFromSourceFile`.
This commit adds a caching mechanism whereby the `AbsoluteFsPath` of a
source file is patched onto the object under an Angular-specific symbol
property, allowing the compiler to avoid resolving the path on subsequent
calls.
PR Close#41475
fab1a6468e