memory safety: audit use of static variables

[junr03]

We should audit the use of static variables in the codebase to prevent static initialization/deinitialization order problems internally, and for dependent projects.

The codebase already defines a construct on first use macro. We should audit other static variables that should be migrated, and enforce the pattern via code linting.

[mattklein123]

There is a clang-tidy rule that can check this. We tried it but then turned it off for some reason. @lizan knows the history here.

[jmarantz]

/sub

[lizan]

There is a check in clang-tidy: https://clang.llvm.org/extra/clang-tidy/checks/fuchsia-statically-constructed-objects.html
We added and reverted in #5733

The problem was tests are registered via static registration mechanism which will be flagged by clang-tidy.

If we wrap those macro, i.e. ENVOY_TEST_F, ENVOY_TEST_P, then we can add NOLINT in the macro definition to workaround that.

[mattklein123]

This has caused enough problems lately that I think we should turn this check on and deal with the macros. @lizan wdyt?

[lizan]

sounds reasonable.