Implement Math.ceil via Math.floor.

src/math.js

Index: src/math.js
diff --git a/src/math.js b/src/math.js
index 789886e2d1c4abf87d0bb2ba5612e35f1f263e33..5cbe94a35c7be9d71024a39b266ec8e920e022b6 100644
--- a/src/math.js
+++ b/src/math.js
@@ -74,7 +74,7 @@ function MathAtan2(y, x) {
 
 // ECMA 262 - 15.8.2.6
 function MathCeil(x) {
-  return %Math_ceil(TO_NUMBER_INLINE(x));
+  return -MathFloor(-x);
 }
 
 // ECMA 262 - 15.8.2.7
@@ -348,6 +348,7 @@ function SetUpMath() {
     "imul", MathImul
   ));
 
+  %SetInlineBuiltinFlag(MathCeil);
   %SetInlineBuiltinFlag(MathRandom);
   %SetInlineBuiltinFlag(MathSin);
   %SetInlineBuiltinFlag(MathCos);