Rename pprof to jeprof.

This rename avoids installation collisions with the upstream gperftools.
Additionally, jemalloc's per thread heap profile functionality
introduced an incompatible file format, so it's now worthwhile to
clearly distinguish jemalloc's version of this script from the upstream
version.

This resolves #229.

Bug: 21326736
(cherry picked from commit 529cffc0e568ca5aa4777e363e7bb5b59700c286)

Change-Id: I3f9f09c65480ee0a840ed6e1c1e041cfef9f06cd
7 files changed