Revert "[clang] Add experimental option to omit the RTTI component from the...

Revert "[clang] Add experimental option to omit the RTTI component from the vtable when -fno-rtti is used"

This reverts commit 6385c1df.

Reverting since this broke a windows builder:
https://lab.llvm.org/buildbot/#/builders/216/builds/27252.