Revert all the changes to equals operator. Causing buildbot trouble.

lib/compiler/implementation/ssa/nodes.dart

Index: lib/compiler/implementation/ssa/nodes.dart
diff --git a/lib/compiler/implementation/ssa/nodes.dart b/lib/compiler/implementation/ssa/nodes.dart
index 750b857eaefe3ebe83815cb9b6a259145516d890..0e075d89c0d78aa0e2e4026d2deb1ba016b51a3f 100644
--- a/lib/compiler/implementation/ssa/nodes.dart
+++ b/lib/compiler/implementation/ssa/nodes.dart
@@ -2042,9 +2042,7 @@ class HEquals extends HRelational {
     // All primitive types have === semantics.
     // Note that this includes all constants except the user-constructed
     // objects.
-    return left.propagatedType.isPrimitive() ||
-        left.isConstantNull() ||
-        right.isConstantNull();
+    return left.isConstantNull() || left.propagatedType.isPrimitive();
   }
 
   HType computeTypeFromInputTypes() {