Add test suite handling to central androidmk code

MTS is introducing partial MTS test suites that are per-module, with
names of the format: mts-${MODULE}. By centralizing the code for test
suites, we can automatically add "mts" test suite when an
"mts-${MODULE}" test suite is specified, reducing duplication.

Test: m mts
Bug: 170318013
Change-Id: I8ce9d3c252fcc0a937bb5f2826d21cb6c6932d82

java/androidmk.go

@@ -139,9 +139,9 @@ func (library *Library) AndroidMkEntries() []android.AndroidMkEntries {
 func testSuiteComponent(entries *android.AndroidMkEntries, test_suites []string) {
 	entries.SetString("LOCAL_MODULE_TAGS", "tests")
 	if len(test_suites) > 0 {
-		entries.AddStrings("LOCAL_COMPATIBILITY_SUITE", test_suites...)
+		entries.AddCompatibilityTestSuites(test_suites...)
 	} else {
-		entries.SetString("LOCAL_COMPATIBILITY_SUITE", "null-suite")
+		entries.AddCompatibilityTestSuites("null-suite")
 	}
 }