Increase constexpr steps limit for clang builds

[cocosolos]

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What does this pull request do?

Double Clang's default constexpr evaluation step limit so the compile-time RNG distribution tests compile reliably with Release build configurations.

#23 2372.8 /server/src/test/tests/rng_spread_tests.cpp:128:15: error: static assertion expression is not an integral constant expression
#23 2372.8   128 | static_assert(spreadWithin<10, kIntSamples>(0xDEADBEEF, 90), "integer spread too skewed");           // within 9%
#23 2372.8       |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#23 2372.8 /server/src/test/tests/rng_spread_tests.cpp:68:5: note: constexpr evaluation hit maximum step limit; possible infinite loop?
#23 2372.8    68 |     {
#23 2372.8       |     ^
#23 2372.8 /server/src/test/tests/rng_spread_tests.cpp:103:12: note: in call to 'maxBucketDeviation<10U, 24000U, Squirrel5>(3735928559)'
#23 2372.8   103 |     return maxBucketDeviation<Buckets, Samples, Engine>(seed) <= allowed;
#23 2372.8       |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#23 2372.8 /server/src/test/tests/rng_spread_tests.cpp:128:15: note: in call to 'spreadWithin<10U, 24000U, Squirrel5>(3735928559, 90)'
#23 2372.8   128 | static_assert(spreadWithin<10, kIntSamples>(0xDEADBEEF, 90), "integer spread too skewed");           // within 9%
#23 2372.8       |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#23 2372.8 1 error generated.

Steps to test these changes

https://github.com/cocosolos/server/actions/runs/28992481674

[zach2good]

We'd ideally set it to just high enough that the current constexpr tests pass, and only set this on the TUs that need it