Some records may need to point to data with the same lifetime as the
records themselves. One solution is to store the data at the end of
the memory pool buffer. Records in the buffer grow up, and the data
grows down. When the buffer is flushed both records and data are
recycled.
Change-Id: I278fa84478236bf895f7c2d152d47d4256987392
[ROCm/roctracer commit: ef3b2a8aa8]
Laurent Morichetti