TimeClip converts -0 to +0, following ES2015 spec

src/date.js

Index: src/date.js
diff --git a/src/date.js b/src/date.js
index a39e538821cb57eddc0447c444b2b0f1c78f83a8..44e8f56e71b05926cdd7ef7f278165d416c2db98 100644
--- a/src/date.js
+++ b/src/date.js
@@ -116,7 +116,7 @@ function MakeDate(day, time) {
 function TimeClip(time) {
   if (!IsFinite(time)) return NAN;
   if (MathAbs(time) > MAX_TIME_MS) return NAN;
-  return TO_INTEGER(time);
+  return TO_INTEGER(time) + 0;
 }
 
 
@@ -144,7 +144,7 @@ function DateConstructor(year, month, date, hours, minutes, seconds, ms) {
     SET_UTC_DATE_VALUE(this, value);
   } else if (argc == 1) {
     if (IS_NUMBER(year)) {
-      value = year;
+      value = TimeClip(year);
 
     } else if (IS_STRING(year)) {
       // Probe the Date cache. If we already have a time value for the