Revert change to EquivalentTime in date.js. The checks that I've removed in t...

src/runtime.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4943 matching lines @@
   static const int day_from_month_leap[] = {0, 31, 60, 91, 121, 152,
                                             182, 213, 244, 274, 305, 335};
 
   year += month / 12;
   month %= 12;
   if (month < 0) {
     year--;
     month += 12;
   }
 
+  ASSERT(month >= 0);
+  ASSERT(month < 12);
+
   static const int base_day = 365*1969 + 1969/4 - 1969/100 + 1969/400;
   int year1 = year - 1;
   int day_from_year = 365 * year1 + year1 / 4 - year1 / 100 + year1 / 400 -
                       base_day;
 
   if (year % 4 || (year % 100 == 0 && year % 400 != 0)) {
     return Smi::FromInt(day_from_year + day_from_month[month] + date - 1);
   } else {
     return Smi::FromInt(day_from_year + day_from_month_leap[month] + date - 1);
   }
@@ skipping 3417 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal