[lldb] Remove test for add-symbol-file adds unwind source

In

commit 2f63718f
Author: Jason Molenda <jmolenda@apple.com>
Date:   Tue Mar 26 09:07:15 2024 -0700

    [lldb] Don't clear a Module's UnwindTable when adding a SymbolFile (#86603)

I changed lldb to not clear a Module's UnwindTable when we add a
SymbolFile to a binary, because the added benefit is marginal, and
handling this reconstruction correctly is difficult.  This test was
written to explicitly create a test without unwind info in the
binary, then add a symbol file with the unwind info, and check that
it is present.  I've intentionally broken this, so I'm removing the
test.