gdb: Introduce "scylla find" command
gdb: Introduce "scylla find" command

Finds live objects on seastar heap of current shard which contain
given value. Prints results in 'scylla ptr' format.

Example:

  (gdb) scylla find 0x600005321900
  thread 1, small (size <= 512), live (0x6000000f3800 +48)
  thread 1, small (size <= 56), live (0x6000008a1230 +32)

Message-Id: <90aed9a822fded2eb8e17e01f16bf66c00d01470@scylladb.com>

duarten/scylla,scylladb/scylla,avikivity/scylla,duarten/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla