https://bugs.webkit.org/show_bug.cgi?id=94810

Reviewed by Benjamin Poulain.

Only tested on BlackBerry. So it is wrapped with PLATFORM(BLACKBERRY) in the mean time.
Use realloc to shrink buffer when inline buffer isn't involved and and canMoveWithMemcpy is true.

When running the test code attached to the bug, it gives 30-45% performance boost for the large blocks
(Every test cycle includes an extra pair of malloc/free, so the boost on shrinkToFit() is even bigger)
Performance impact on small blocks is not noticeable. (Tested on BlackBerry)

* wtf/Vector.h:
(WTF::VectorBufferBase::shouldReallocateBuffer):
(VectorBufferBase):
(WTF::VectorBufferBase::reallocateBuffer):
(VectorBuffer):
(WTF::VectorBuffer::shouldReallocateBuffer):
(WTF::VectorBuffer::reallocateBuffer):
(WTF::VectorBuffer::inlineBuffer):
(WTF::::shrinkCapacity):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@127186 268f45cc-cd09-0410-ab3c-d52691b4dbfc