Before this change, running check-lldb-shell with LLVM_ENABLE_DIA_SDK=NO would fail ~25 tests.
This change adds a lit feature based on if the DIA SDK is available and annotates
all tests that set breakpoints with this new feature. Now these tests are skipped
(with a warning message during test startup) instead of failing. This matches how
this is handled in check-llvm.
(This doesn't touch API or Unit tests for now.)