[lldb/Test] Don't add a check-* target as dependency in add_lit_testsuite

This causes the toplevel "test-depends" target, which should only build
all the dependencies necessary for running tests, to suddenaly also run
the check-lldb-repro-capture tests.

Instead add check-lldb-repro-capture as a dependency to check-lldb-repro
with a separate explicit add_dependencies call.