Use Long/Integer.compare in other desugaring implementations

These will themselves be desugared, if necessary.

Test: tools/test.py --dex_vm all --no-internal *Java8Methods*
Change-Id: Iabdd7d6e4c2c973145f62a9bc2972fbf9deacdbb
diff --git a/src/main/java/com/android/tools/r8/ir/desugar/Java8MethodRewriter.java b/src/main/java/com/android/tools/r8/ir/desugar/Java8MethodRewriter.java
index 69d0b48..89782b6 100644
--- a/src/main/java/com/android/tools/r8/ir/desugar/Java8MethodRewriter.java
+++ b/src/main/java/com/android/tools/r8/ir/desugar/Java8MethodRewriter.java
@@ -257,7 +257,7 @@
     public static int compareUnsignedImpl(int a, int b) {
       int aFlipped = a ^ Integer.MIN_VALUE;
       int bFlipped = b ^ Integer.MIN_VALUE;
-      return (aFlipped < bFlipped) ? -1 : ((aFlipped > bFlipped) ? 1 : 0);
+      return Integer.compare(aFlipped, bFlipped);
     }
   }
 
@@ -517,7 +517,7 @@
     public static int compareUnsignedImpl(long a, long b) {
       long aFlipped = a ^ Long.MIN_VALUE;
       long bFlipped = b ^ Long.MIN_VALUE;
-      return (aFlipped < bFlipped) ? -1 : ((aFlipped > bFlipped) ? 1 : 0);
+      return Long.compare(aFlipped, bFlipped);
     }
   }