DataRowTest: null-cases test of getStringValue
tests setups: createRow(int...) -> (Integer...)
Avoid primitive arrays since is too much hassle when converting to List
Add createRow(List) to DiffTestUtils
tests: add HasMatchStatus matcher
Used to verify status of a MatchResult (single and collection)
Parameterized tests for some DataRowDiff int tests
Tidy up DataRowDiffTest