lowering: Don't bother rewrapping bare linenumbers in hygienic-scope (#53850)
JuliaInterpreter tries to do some very questionable pre-lowering
introspection to find line numbers, but doesn't properly handle hygienic
scope. That should be fixed, but as I was about to put in a hack there,
I figured we might as well not bother re-wrapping bare LineNumberNodes
in hygienic scopes. They just get discarded again immediately anyway. No
functional change in that this is semantically equivalent to what we had
before, just with a slightly more compact lowering result and additional
JuliaInterpreter test passing.