[clang] [clang][NFC] Simplify implementation of `IgnoreExprNodes` (PR #164193)

[Victor Chernyakin via cfe-commits]

localspook wrote:

We have a couple with 3 functions:
https://github.com/llvm/llvm-project/blob/4d6f43d64f07f5adc9f37212756794e20b4ae8c5/clang/lib/Sema/SemaStmt.cpp#L691-L693
https://github.com/llvm/llvm-project/blob/4d6f43d64f07f5adc9f37212756794e20b4ae8c5/clang/lib/Tooling/Syntax/BuildTree.cpp#L75-L77
Beyond that, I don't see any examples with 4+

https://github.com/llvm/llvm-project/pull/164193