Use assertSame in LogFormatterTestCase

Use assertSame in LogFormatterTestCase

Using assertSame also checks for internal types to be correct.

Needs the following fixes:
- MergeLogFormatterTest: Use correct array key order
- NewUsersLogFormatterTest: Input user id as integer
- PatrolLogFormatter: Ensure in LogFormatter that
  integer is not casted to float

Change-Id: I2cab5335d6654f6cda15fc4e9fbae2c1ca1b27ff