* sverker/bug-fixing:
  erts: Fix erts_debug:set_internal_state(reds_left)
  erts: Fix binary_SUITE:cmp_old_impl

to avoid failed ERTS_DBG_CHK_REDS by clearing virtual_reds.

since DFLAG_BIG_CREATION became mandatory in
321dc6ee0241f802c940def174c0a77262e11f21.

* lukas/erts/fragment-dist-messages/OTP-13397/OTP-15610/OTP-15611/OTP-15612/OTP-15613/OTP-15703: (26 commits)
  erts: Yield when exiting/free process is suspended by de
  doc: Fix Design Princ, statem incorrect anchor
  erts: Include external msg in need of GC
  erts: Include dist header in return from dist_ctrl_get_data
  erts: Fix so that exit/down terms stay alive
  erts: Pending signals can be for free processes
  erts: Fix faulty assert in reference_table_term
  etp: Don't crash etp-stack* when c_p->i is null
  erts: Adjust dist obuf size correctly after hdr fin
  erts: Fix non-payload dist exit signals
  erts: Always do trylock on proc locks when crash dumping
  Fix tests to work better in debug emulator
  erts: erts_factory_proc_init should not set hole marker
  erts: Skip heavy process tab tests in debug emu
  ts: Use same dynlinking logic for all bsd
  Revert "erts: Always run fds check after each testcase"
  erts: Always run fds check after each testcase
  erts: Always stop any testnodes before testcase exits
  erts: Add crash dumping of EXITING and FREE processes
  wx: Remove ERL_FLAGS from Makefile erlc command
  ...

When many external messages suddenly appear in the mailbox
the young gen size is adjusted accordingly but it was
immediately shrunk as the data was not counted towards the
shrink size. This commit includes the ext dist size in the
shrink calculation which means that the decode of the external
messages will not trigger as many GCs which means much better
performance.