[llvm] [WebAssembly] Align bulk-memory thresholds (PR #134816)

[Derek Schuff via llvm-commits]

dschuff wrote:

Have you actually run any tests on any of the engines? Emscripten only actually uses bulk memory for larger memcpy by default because there's a bit of overhead compared to just using loads and stores for small memcpy. It was my intention to do some more comprehensive testing (especially with SIMD available) but I hadn't gotten around to it.

https://github.com/llvm/llvm-project/pull/134816