Optimize getLoggableTypes in fuzzer, and add isLoggableType (#3208)
Optimize getLoggableTypes in fuzzer, and add isLoggableType (#3208)

Previously getLoggableType would allocate a vector every time. This
caches it.

Also add isLoggableType which will need this caching as I will be
calling it quite a lot in a future patch to the fuzzer.
WebAssembly/binaryen,WebAssembly/binaryen,WebAssembly/binaryen,WebAssembly/binaryen,WebAssembly/binaryen