Added new tests for SaveInfo.

Also changed some exception-related tests to use TestNg for consistency.

Bug: 38044993

Test: SaveInfoTest
Test: LoginActivityTest.testSaveNoRequiredField_NoneFilled()
Test: LoginActivityTest.testSaveNoRequiredField_OneFilled()
Test: LoginActivityTest.testSaveNoRequiredField_BothFilled()

Change-Id: Ifab511fbb17256f3414aaa11c0c0f83005bcac45
9 files changed