Fix all backwards (-1 == x) tests.

Change-Id: Idbee45f00da4e107fcdcf0b4c66f3a485c9e1972
diff --git a/luni/src/main/java/java/io/BufferedInputStream.java b/luni/src/main/java/java/io/BufferedInputStream.java
index 5a810e7..84a3708 100644
--- a/luni/src/main/java/java/io/BufferedInputStream.java
+++ b/luni/src/main/java/java/io/BufferedInputStream.java
@@ -325,7 +325,7 @@
         if (buf == null) {
             throw new IOException("Stream is closed");
         }
-        if (-1 == markpos) {
+        if (markpos == - 1) {
             throw new IOException("Mark has been invalidated.");
         }
         pos = markpos;
diff --git a/luni/src/main/java/java/util/EnumMap.java b/luni/src/main/java/java/util/EnumMap.java
index 827fb51..dfacb46 100644
--- a/luni/src/main/java/java/util/EnumMap.java
+++ b/luni/src/main/java/java/util/EnumMap.java
@@ -174,7 +174,7 @@
         @Override
         @SuppressWarnings("unchecked")
         public String toString() {
-            if (-1 == prePosition) {
+            if (prePosition == -1) {
                 return super.toString();
             }
             return type.get(
@@ -183,7 +183,7 @@
         }
 
         private void checkStatus() {
-            if (-1 == prePosition) {
+            if (prePosition == -1) {
                 throw new IllegalStateException();
             }
         }