Rollup merge of #53110 - Xanewok:save-analysis-remap-path, r=nrc

Account for --remap-path-prefix in save-analysis

Fixes #52549.

Didn't add a test since save-analysis is still unstable, only tested this locally. Should I add a test for that? If so, is run-make-fulldeps an appropriate format?

Session is already created with remapped working directory, so use that instead of the actual cwd.
This was the only place affected, since the rest of the paths in save-analysis are directly derived from files in spans from `sess.codemap()`, which already creates remapped ones.

r? @nrc

diff --cc src/librustc_save_analysis/lib.rs
Simple merge