testsuite: expand size testing infrastructure

- closes #24191
- adds windows_skip, wasm_skip, wasm_arch, find_so, _find_so
- path_from_ghcPkg, collect_size_ghc_pkg, collect_object_size, find_non_inplace functions to testsuite
- adds on_windows and req_dynamic_ghc predicate to testsuite

The design is to not make the testsuite too smart and simply offload to
ghc-pkg for locations of object files and directories.