Check and mark tests related to new features in 2.x

[ArBridgeman]

Summary

These tests should be investigated and if they still don't work marked differently as they relate to new features & would not be addressed in the beta-release:

• ComponentReflectionTest.test_get_multi_columns -> works fully with modifications
• ComponentReflectionTest.test_get_multi_foreign_keys -> works fully with modifications
• ComponentReflectionTest.test_get_multi_pk_constraint -> works

Additionally, the default implementation of sqlalchemy should be checked to make sure a sensible error is being tossed and if not this should be adapted. The PM should also be made aware of these features for future prioritization effort. In order to do this, please make one or more issues detailing the work & estimating the effort.

Also, do:

• Check that all XFAILS have strict=True whenever possible

[ArBridgeman]

closed with #655