gh-115556: Remove quotes from command-line arguments in test.bat and rt.bat (#115557)

This change essentially replaces usage of `%1` with `%~1`, which removes
quotes, if any. Without this change, the if statements fail due to
the quotes mangling the syntax.

Additionally, this change works around comma being treated as a parameter
delimiter in test.bat by escaping commas at time of parsing. Tested
combinations of rt and regrtest arguments, all seems to work as before
but now you can specify commas in arguments like "-uall,extralargefile".