- 1MiB objects on the stack doesn't play well with wasmtime.
Reduce these to 512KiB so that the webassembly benchmarks can run.
- Pass expected results to a blackBox() function. Without this, in
release-fast mode, the compiler could detected unused return values,
and would produce results that didn't make sense for siphash.
- Add AEAD constructions to the benchmarks.
- Inline chacha20Core() makes it 4 times faster.
- benchmarkSignatures() -> benchmarkSignature() for consistency.