Get rid of fastMallocGoodSize() and replace it with something generic.

Source/wtf/FastMalloc.h

Index: Source/wtf/FastMalloc.h
diff --git a/Source/wtf/FastMalloc.h b/Source/wtf/FastMalloc.h
index 1e05db286730fc68afcde6c9679c1872317f96e4..3123c914b1188659e7d5258c14f80d2c48b5ed4d 100644
--- a/Source/wtf/FastMalloc.h
+++ b/Source/wtf/FastMalloc.h
@@ -32,7 +32,6 @@ namespace WTF {
     WTF_EXPORT void* fastCalloc(size_t numElements, size_t elementSize);
     WTF_EXPORT void* fastRealloc(void*, size_t);
     WTF_EXPORT char* fastStrDup(const char*);
-    WTF_EXPORT size_t fastMallocGoodSize(size_t);
 
     WTF_EXPORT void fastFree(void*);
 
@@ -59,7 +58,6 @@ namespace WTF {
 using WTF::fastCalloc;
 using WTF::fastFree;
 using WTF::fastMalloc;
-using WTF::fastMallocGoodSize;
 using WTF::fastRealloc;
 using WTF::fastStrDup;
 using WTF::fastZeroedMalloc;