[runtime] Remove obsolete %ObjectEquals runtime entry.

src/debug/mirrors.js

Index: src/debug/mirrors.js
diff --git a/src/debug/mirrors.js b/src/debug/mirrors.js
index 1fd5fa9ecd7222dca3026e5c48e848f3127d33b2..8b9dd02b6ea0bd5cc029b3b16499df0b1fe948c7 100644
--- a/src/debug/mirrors.js
+++ b/src/debug/mirrors.js
@@ -812,7 +812,7 @@ ObjectMirror.prototype.lookupProperty = function(value) {
     // Skip properties which are defined through accessors.
     var property = properties[i];
     if (property.propertyType() != PropertyType.AccessorConstant) {
-      if (%_ObjectEquals(property.value_, value.value_)) {
+      if (property.value_ === value.value_) {
         return property;
       }
     }