Update tests to use new water files; add angle SMIRKS for water to test ffxml.
Update tests to use new water files; add angle SMIRKS for water to test ffxml.

open-forcefield-group/openforcefield,openforcefield/openff-toolkit,open-forcefield-group/openforcefield,open-forcefield-group/openforcefield,openforcefield/openff-toolkit