[clang] [LifetimeSafety] Model GNU statement expressions (PR #204841)

[Utkarsh Saxena via cfe-commits]

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@@ -0,0 +1,55 @@
+// RUN: %clang_cc1 -fsyntax-only -Wlifetime-safety -Wno-gnu-statement-expression -verify %s
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usx95 wrote:

Since extensions warnings are default off, can we remove this flag and thereby move this test to existing file ?

https://github.com/llvm/llvm-project/pull/204841