Add unit test for uidMatchTypeToString function

uidMatchTypeToString function has no enough line coverage currently.
Add a simple unit test so that code lines can be executed and counted.

NO_MATCH(0) can't be verified because match type flag is added by OR
operator. See TrafficController::addRule.

Bug: N/A
Test: atest
Change-Id: I6178d4a8cc21430882fae3c1f53f7bc1cebb6c01
1 file changed