Try demangling names before forwarding them to the profiler

[bnjbvr]

Before this PR, each profiler (perf/vtune, at the moment) had to have a
demangler for each of the programming languages that could have been
compiled to wasm and fed into wasmtime. With this, wasmtime now
demangles names before even forwarding them to the underlying profiler,
which makes for a unified representation in profilers, and avoids
incorrect demangling in profilers.

[alexcrichton]

Oh oops looks like I was too slow, but in any case this is actually a duplicate of this demangling logic so if you're up for it it'd be great to have some sort of helper function in wasmtime-jit which wasmtime::Trap calls into and this function shares as well.

Similarly if you're interested in pushing on vtune one feature the vtune support is missing is loading profiling information for trampolines. Trampolines were added recently to jitdump support but were skipped as part of vtune since I didn't know how to modify it.

[bnjbvr]

@alexcrichton, I will look into this!