catchorg/Catch2 v3.16.0 on GitHub

Multiple fixes in catch_discover_tests:
- Fixed <target>_TESTS variable accumulating JSON fragments alongside test names.
  - This was introduced during the refactoring in last release.
- Fixed <target>_TESTS variable from catch_discover_tests not escaping test names to be properly parsed by CMake.
  - This means that e.g. test names with semicolons will not be split into multiple partial test names.
  - This bug has existed since the first version of the script.
- Fixed TEST_PREFIX/TEST_SUFFIX args having leading/trailing whitespace stripped.
Added workaround for Clang 20-21 compile error with TEMPLATE_PRODUCT_TEST_CASE (#3115, #3173)

Verbosity option is now handled per reporter.
- The standalone --verbosity flag is propagated to all reporters as default, just like --colour-mode.
The JSON reporter considers verbosity when listing tests.
Another set of performance improvements for catch_discover_tests performance
- The newest version can register about 3k tests in 1 second, up from 1k previously.
The initial TEST_CASE registration is slightly faster.
Reduced overhead from first instantiating BENCHMARK machinery in a TU.
Improved compilation speed when multiple templated test case macros use the same types.
Rewrote implementation of the string matchers
- Case-sensitive matching (the default) is significantly faster.
- Case-insensitive matching is faster in most cases.
Added optimizer barrier to calls into benchmarks without return values
- This limits the optimizations compiler can perform between calls into the benchmarked function, improving the accuracy.
Added warning that checks for using sharding without deterministic test order (#3186)