[clang] [clang][test] add TestLanguage.def to specify all tested language versions (PR #94243)

[via cfe-commits]

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@@ -1224,7 +1224,7 @@ TEST_P(ASTMatchersTest, CastExpression_MatchesImplicitCasts) {
 }
 
 TEST_P(ASTMatchersTest, CastExpr_DoesNotMatchNonCasts) {
-  if (GetParam().Language == Lang_C89 || GetParam().Language == Lang_C99) {
+  if (GetParam().isC()) {
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Sirraide wrote:

Don’t we need `isCOrEarlier()` here?

https://github.com/llvm/llvm-project/pull/94243