Figure out how to reference files for tests in WASM

[DrewScoggins]

Currently we use Assembly.Location to build the path for opening files in performance tests, but this does not work on WASM. We should come up with a way to do this.

[DrewScoggins]

They are disabled for those other tests. I vaguely remember having this discussion before when we were first standing up WASM runs, but I can't find anything about it right now. As for best practices for locating a file, I don't believe we have anything except for what is already checked in. For tests running in the lab we could build the path from scratch using environment variables that we have on running machines, but that would not solve the issue of how we locate the files locally. Maybe @naricc has some insight on the best way to get at the base location in WASM.

From #2162

[naricc]

There are MSbuild properties that can be set to include arbitrary files in a the wasm virtual file system, I think that would work. BenchmarkDotnet would need to be modified to add those parameters to the generated project though, and then we would need the path to those files when the benchmark project was built (or I could go implement the Source Generator tool chain dotnet/BenchmarkDotNet#1770).

I don't recall exactly what those properties are. @radical @akoeplinger Do you happen to recall?

[radical]

@(WasmFilesToIncludeInFileSystem)