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
diff --git a/java/java_test.go b/java/java_test.go
index 2f67cda..30a8ca6 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -486,6 +486,13 @@
 			name: "stubs-source",
 			srcs: ["stubs/sources"],
 		}
+
+		java_test_import {
+			name: "test",
+			jars: ["a.jar"],
+			test_suites: ["cts"],
+			test_config: "AndroidTest.xml",
+		}
 		`)
 
 	fooModule := ctx.ModuleForTests("foo", "android_common")