Update V8 to r7427: Initial merge by git

As required by WebKit r82507

Change-Id: I7ae83ef3f689356043b4929255b7c1dd31d8c5df
diff --git a/test/mjsunit/str-to-num.js b/test/mjsunit/str-to-num.js
index 28e98d9..bbfa7d3 100644
--- a/test/mjsunit/str-to-num.js
+++ b/test/mjsunit/str-to-num.js
@@ -190,7 +190,7 @@
 assertEquals(Infinity,  toNumber("1e999"), "1e999");
 assertEquals(-Infinity, toNumber("-1e999"));
 assertEquals(0,         toNumber("1e-999"));
-assertEquals(0,         toNumber("-1e-999"));
+assertEquals(-0,        toNumber("-1e-999"));
 assertEquals(Infinity,  1 / toNumber("1e-999"), "1e-999");
 assertEquals(-Infinity, 1 / toNumber("-1e-999"));