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

lib/compiler/implementation/ssa/builder.dart

Index: lib/compiler/implementation/ssa/builder.dart
diff --git a/lib/compiler/implementation/ssa/builder.dart b/lib/compiler/implementation/ssa/builder.dart
index 4041d33c8e79866db86cb2f6cb5e629ffde6f46a..6feb3d81e799b1e0508dac5eb6c75cc7aec23a81 100644
--- a/lib/compiler/implementation/ssa/builder.dart
+++ b/lib/compiler/implementation/ssa/builder.dart
@@ -97,6 +97,10 @@ class Interceptors {
     return compiler.findHelper(const SourceString('indexSet'));
   }
 
+  Element getEqualsNullInterceptor() {
+    return compiler.findHelper(const SourceString('eqNull'));
+  }
+
   Element getExceptionUnwrapper() {
     return compiler.findHelper(const SourceString('unwrapException'));
   }