Use common helper functions for getting sorted map keys.

Add a new helper SortedIntKeys similar to SortedStringKeys.

Test: lunch aosp_cf_x86_phone-userdebug && m
Change-Id: I08a43ec2cae7d1a82531295aca1a0658e3a0dd6f

java/java_test.go

@@ -1495,7 +1495,7 @@ func TestJavaSdkLibrary(t *testing.T) {
 	// test if baz has exported SDK lib names foo and bar to qux
 	qux := ctx.ModuleForTests("qux", "android_common")
 	if quxLib, ok := qux.Module().(*Library); ok {
-		sdkLibs := quxLib.ExportedSdkLibs().Names()
+		sdkLibs := android.SortedStringKeys(quxLib.ExportedSdkLibs())
 		if w := []string{"bar", "foo", "fred", "quuz"}; !reflect.DeepEqual(w, sdkLibs) {
 			t.Errorf("qux should export %q but exports %q", w, sdkLibs)
 		}