[clang] Revert "[clang-cl] Add new option `/pathmap:<from>=<to>` to replace the path prefix <from> with <to>." (PR #201981)

[Vladimir Vereschaka via cfe-commits]

vvereschaka wrote:

Failed build for the record: https://lab.llvm.org/buildbot/#/builders/190/builds/43598

https://github.com/llvm/llvm-project/pull/201981