[lldb][test] TestConstStaticIntegralMember.py: fix on older clang versions

`638a8393` removed the `dsym`
condition for older compiler versions which caused the `dwarf`
variants tests to XPASS. This patch reverts to only XFAIL-ing
the `dsym` variant.

`15c80852` added
`test_shadowed_static_inline_members` which isn't supported
on older compiler versions.