The assert added in
[0ab1d23fbfa2ae0ba14315cb11678d2289510f66](0ab1d23fbf)
is incorrect, NewUnit is legitimately null for compile units that are
skipped during garbage collection (e.g. dwarf5-macro.test). Revert to
the original null check.
The assert added in
[0ab1d23fbfa2ae0ba14315cb11678d2289510f66](0ab1d23fbf)
is incorrect, NewUnit is legitimately null for compile units that are
skipped during garbage collection (e.g. dwarf5-macro.test). Revert to
the original null check.