meson: valgrind wrapper should return correct errors

meson: valgrind wrapper should return correct errors

While trying to raise an exception on failures, it instead raised an
exception for misusing the exception. CalledProcessError is only
supposed to be used when given a return code and a command, and it
prints:

Command '{cmd}' returned non-zero exit status {ret}

Passing an error message string instead, just errored out with:

TypeError: __init__() missing 1 required positional argument

Instead use the subprocess module's base error which does accept string
messages. Everything that used to error out, still errors out, but now
they do so with a slightly prettier console message.