[clang][C++20] Fix clang/clangd assert/crash after compilation errors

After compilation errors, expression a transformation result may not be usable.
It triggers an assert in RemoveNestedImmediateInvocation and SIGSEGV in case of
builds without asserts. This issue significantly affects clangd because source
may not be valid during typing. Tests cases that I attached was reduce from huge
C++ translation unit.

Test Plan: check-clang

Differential Revision: https://reviews.llvm.org/D133948