)

* filesystem: fill in remaining todo'd methods which have wasi-common implementations

* turn on fd_filestat_set, path_rename_dir_trailing_slashes, and symlink_filestat tests, which now pass

* change expect_fail to a function

* filesystem set flags: return Notsup instead of panic

This PR changes the `isaspec` tool to generate multiple files.

As we extend the use of ASLp, we are generating a lot of spec code. This
is especially true for `BitRR` which we'll be adding soon. Allowing the
tool to generate more than one file will hopefully make them a bit more
manageable.

Updates #35 avanhatt#62

Implement SIMD128 support