Avoid heapprofd init when other hooks enabled.

All of the heapprofd code assumes that it's the only hook that
has been enabled. Enforce that by disallowing heapprofd from
enabling if malloc debug or malloc hooks have been enabled.

Test: Ran all unit tests (bionic/malloc hooks/malloc debug/perfetto).
Test: Enabled malloc debug ran perfetto integration tests and verified
Test: that an error message goes to the log.
Change-Id: I506fbf1c5b8e4052855531fa0d161f5de06e6c1a