[LLD] [COFF] Fix handling of comdat .drectve sections (#68116)

This can happen when manually emitting strings into .drectve sections
with `__attribute__((section(".drectve")))`, which is a way to emulate
`#pragma comment(linker, "...")` for mingw compilers, without requiring
building with -fms-extensions.

Normally, this doesn't generate any comdat, but if compiled with
-fsanitize=address, this section does get turned into a comdat section.

This fixes #67261. This issue can be seen as a regression; a change in
the "lli" tool in 17.x triggers this case, if compiled with ASAN
enabled, triggering this unsupported corner case in LLD. With this
change, LLD can handle it.

(cherry picked from commit 503bc5f6)