Fix broken test in WebKit test suite and add the test in question to V8 tests...

src/runtime.cc

Index: src/runtime.cc
===================================================================
--- src/runtime.cc	(revision 4006)
+++ src/runtime.cc	(working copy)
@@ -4969,9 +4969,25 @@
   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 -
+  // year_delta is an arbitrary number such that:
+  // a) year_delta = -1 (mod 400)
+  // b) year + year_delta > 0 for years in the range defined by
+  //    ECMA 262 - 15.9.1.1, i.e. upto 100,000,000 days on either side of
+  //    Jan 1 1970. This is required so that we don't run into integer
+  //    division of negative numbers.
+  // c) there shouldn't be overflow for 32-bit integers in the following
+  //    operations.
+  static const int year_delta = 399999;
+  static const int base_day = 365 * (1970 + year_delta) +
+                              (1970 + year_delta) / 4 -
+                              (1970 + year_delta) / 100 +
+                              (1970 + year_delta) / 400;
+
+  int year1 = year + year_delta;
+  int day_from_year = 365 * year1 +
+                      year1 / 4 -
+                      year1 / 100 +
+                      year1 / 400 -
                       base_day;
 
   if (year % 4 || (year % 100 == 0 && year % 400 != 0)) {