Fix code cleanups (#1441)

* Fix immutable properties

It was intentionally designed the previous way

* Restore limit in for loop

* Another ImmutableProperties

moshi/src/main/java/com/squareup/moshi/Moshi.java

@@ -185,7 +185,7 @@ public final class Moshi {
   @CheckReturnValue
   public Moshi.Builder newBuilder() {
     Builder result = new Builder();
-    for (int i = 0; i < lastOffset; i++) {
+    for (int i = 0, limit = lastOffset; i < limit; i++) {
       result.add(factories.get(i));
     }
     for (int i = lastOffset, limit = factories.size() - BUILT_IN_FACTORIES.size(); i < limit; i++) {