Add support for java_test in sdk

Adds java_test_import module type for use by the sdk snapshot and
adds java_tests property to the sdk and sdk_snapshot module type.

This is needed for the conscrypt test sdk.

Bug: 143678475
Test: m nothing
Change-Id: Ied4c56c978dac2f92a9b3bc34b3235d7eeba2fd3

java/testing.go

@@ -34,6 +34,7 @@ func TestConfig(buildDir string, env map[string]string, bp string, fs map[string
 		"GENRULE_NOTICE":         nil,
 		"LIB_NOTICE":             nil,
 		"TOOL_NOTICE":            nil,
+		"AndroidTest.xml":        nil,
 		"java-res/a/a":           nil,
 		"java-res/b/b":           nil,
 		"java-res2/a":            nil,