Remove wtf_ceil.

Source/platform/Decimal.cpp

Index: Source/platform/Decimal.cpp
diff --git a/Source/platform/Decimal.cpp b/Source/platform/Decimal.cpp
index 93244091171c31638821b69651d5a1bf9fce3f2f..35b5a8aaf4e6ccb7b197748fb647de2968e950fc 100644
--- a/Source/platform/Decimal.cpp
+++ b/Source/platform/Decimal.cpp
@@ -617,8 +617,7 @@ static bool isMultiplePowersOfTen(uint64_t coefficient, int n)
 }
 
 // Round toward positive infinity.
-// Note: Mac ports defines ceil(x) as wtf_ceil(x), so we can't use name "ceil" here.
-Decimal Decimal::ceiling() const
+Decimal Decimal::ceil() const
 {
     if (isSpecial())
         return *this;
@@ -895,7 +894,7 @@ Decimal Decimal::nan()
 Decimal Decimal::remainder(const Decimal& rhs) const
 {
     const Decimal quotient = *this / rhs;
-    return quotient.isSpecial() ? quotient : *this - (quotient.isNegative() ? quotient.ceiling() : quotient.floor()) * rhs;
+    return quotient.isSpecial() ? quotient : *this - (quotient.isNegative() ? quotient.ceil() : quotient.floor()) * rhs;
 }
 
 Decimal Decimal::round() const