[llvm] [libcxx] [libc++][hardening] Rework macros for enabling the hardening mode. (PR #70575)

[Louis Dionne via llvm-commits]

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@@ -9,12 +9,15 @@
 // This test checks that if no hardening mode is defined (i.e., in the unchecked mode), by default assertions aren't
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ldionne wrote:

Filename `unchecked.pass.cpp` -> `none.pass.cpp`?

https://github.com/llvm/llvm-project/pull/70575