I accidentally replaced a couple usages of `AllocatedSize` with
`GetAllocatedSize()`. This resulted in a JIT buffer that ran out of
space would actually allocate a slightly smaller buffer each time, and
then it cascades downwards resulting in catastrophic performance.
Fix the use in `SharedCodeBufferManager.cpp` and `Core.cpp` which were
incorrect and renames the function to be more explicit.
Ryan Houdek
db3817a260