[clang] [clang] Clear `NeedsCleaning` flag after `ExpandBuiltinMacro` (PR #133574)

[Aaron Ballman via cfe-commits]

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@@ -1646,7 +1646,6 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
 
   // Set up the return result.
   Tok.setIdentifierInfo(nullptr);
-  Tok.clearFlag(Token::NeedsCleaning);
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AaronBallman wrote:

There are early returns between where we used to clear the needs cleaning flag and where we set it now; doesn't this mean we'll leave the flag in "needs cleaning" state in circumstances where it won't need cleaning (e.g., when dealing with `__DATE__`)?

https://github.com/llvm/llvm-project/pull/133574