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
diff --git a/java/androidmk.go b/java/androidmk.go
index 144268f..b1582d9 100644
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -121,7 +121,7 @@
 						entries.SetPath("LOCAL_SOONG_JACOCO_REPORT_CLASSES_JAR", library.jacocoReportClassesFile)
 					}
 
-					entries.AddStrings("LOCAL_EXPORT_SDK_LIBRARIES", library.exportedSdkLibs.Names()...)
+					entries.AddStrings("LOCAL_EXPORT_SDK_LIBRARIES", android.SortedStringKeys(library.exportedSdkLibs)...)
 
 					if len(library.additionalCheckedModules) != 0 {
 						entries.AddStrings("LOCAL_ADDITIONAL_CHECKED_MODULE", library.additionalCheckedModules.Strings()...)
diff --git a/java/java_test.go b/java/java_test.go
index 0089545..0e93611 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -1495,7 +1495,7 @@
 	// 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)
 		}