Remove AutofillValueTest from widget TEST_MAPPING

There were some integration tests in AutofillValueTest before, we
moved integration tests to CheckoutActivityTest. AutofillValueTest is
a unit test now, we don't need this test running under widget path.

Bug: 167847110
Test: TreeHugger
Change-Id: I514942cff0122539ac614798020ecbbaf7cbaa3c