With `Type.bool`, size is 1, so dividing by 8 isn't the right way to convert to byteSize. Instead, we need to use the `byteSize` property that does the proper ceiling division.
Remaining implementations of JavaScript's Math functions (except sin/cos/tan), both double (Math) and single (Mathf) precision, ported from musl incl. tests from libc-test, plus some changes to match JS semantics. Also binds fmod to `%` and pow to `**`.
