[clang] [analyzer] Avoid unnecessary super region invalidation in `CStringChecker` (PR #146212)

[Donát Nagy via cfe-commits]

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@@ -0,0 +1,106 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core -verify %s
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NagyDonat wrote:

Please ensure that (the relevant parts of) `CStringChecker` is actually enabled in this test file -- its sub-checkers are in the `unix.cstring` and `alpha.unix.cstring` packages, while this `RUN` line only enables `core`.

As a sanity check it would be nice to have a testcase that actually produces some diagnostics.

https://github.com/llvm/llvm-project/pull/146212