The windows wrappers for basic functions like `os.symlink`,
`os.readlink` and `os.path.islink` in the `llnl.util.symlink` module
have bugs, and trigger more file system operations on non-windows than
they should.
This commit just binds `llnl.util.symlink.symlink = os.symlink` etc so
built-in functions are used on non-windows
e461234865