Alternative cleanup process for temporary files created by test

[loganek]

As pointed in https://github.com/bytecodealliance/wasmtime/pull/6343#discussion_r1185541513, instead of c, instead of expecting tests to suffix all temporary files with .cleanup we might create a temporary working directory and copy all the test-related files/directories there from source, so at the end of the test the whole directory can be removed.

This issue is to explore this alternative and possibly implement it.