Replace SortedStringKeys with SortedKeys

Now that we have generics.

Bug: 193460475
Test: presubmits
Change-Id: I1594fd8feb505175d5c09c03ef397e5ffd5b09cb

cc/library_sdk_member.go

@@ -405,7 +405,7 @@ func addPossiblyArchSpecificProperties(sdkModuleContext android.ModuleContext, b
 	}
 
 	// Add the collated include dir properties to the output.
-	for _, property := range android.SortedStringKeys(includeDirs) {
+	for _, property := range android.SortedKeys(includeDirs) {
 		outputProperties.AddProperty(property, includeDirs[property])
 	}