Add dict:is_empty/1 and orddict:is_empty/1

dict:size/1 runs in constant time, but orddict:size/1 does not.  With
this change, the two modules stay API compatible and gain a
constant-time function for checking whether a dictionary is empty.
Update primary bootstrap
ssl: fix initialization of DTLS fragment reassembler

The DTLS fragment reassembler use a list [{Start, End}] for the
fragments. When the first received fragment was not the starting
fragment, that list got initialized with [{Start, Length}],
causing the merge of following fragment to fail.
Fix broken DWA

Commit e762d7d1 broke outgoing DWA by setting new Hop-by-Hop and
End-to-End identifiers instead of those of the incoming DWR.
Add more SCTP errors as described in RFC 4960
Add iodata, nonempty_string to built-in type highlighting for emacs

These built-in types were missing from emacs highlighting
Update primary bootstrap
Spec for atan2 should be atan2(Y, X), not atan2(X, Y)
Don't try to add the log_mf_h handler in sasl unless configured to do so.

The functions add_error_logger_mf/1 and delete_error_logger_mf/1 in sasl.erl
are designed to do nothing if the handler configuration as returned by
get_error_logger_mf/0 is 'undefined'. However, that function returns a
triple {undefined,undefined,undefined} when the error_logger_mf_*
configurations have not been set. This makes SASL always try to add the
log_mf_h handler on startup, passing 'undefined' for each of the Dir, MaxB
and MaxF parameters. The gen_event callback function log_mf_h:init/1 will
then crash with a function_clause error, causing the handler to be silently
removed again. This patch fixes the problem by making get_error_logger_mf/0
return the single atom 'undefined' as it is expected to do.
erts: Fix memory leak for distributed monitors
Merge branch 'mh/dict_orddict_is_empty/OTP-11353'

* mh/dict_orddict_is_empty/OTP-11353:
  Update primary bootstrap
  Add dict:is_empty/1 and orddict:is_empty/1
tools: Add Erlang-specific compilation error regexp for erlang-eunit

This defvar was removed in a87a9699735b0a25f99397fba9576f5756da54d3 which made
eunit fail on running tests in emacs.
Merge branch 'fredrik/tools/emacs_eunit_regexp/OTP-11417' into maint

* fredrik/tools/emacs_eunit_regexp/OTP-11417:
  tools: Add Erlang-specific compilation error regexp for erlang-eunit
Merge branch 'maint'
Merge branch 'ates/sctp_errors_fix/OTP-11379' into maint

* ates/sctp_errors_fix/OTP-11379:
  Update primary bootstrap
  Add more SCTP errors as described in RFC 4960
Merge branch 'maint'
Merge branch 'RoadRunnr/fix_dtls_fragment_decoder/OTP-11376'

* RoadRunnr/fix_dtls_fragment_decoder/OTP-11376:
  ssl: fix initialization of DTLS fragment reassembler
Remove test_server_h from cover spec file
Merge branch 'peppe/common_test/cover_problem' into maint

* peppe/common_test/cover_problem:
  Remove test_server_h from cover spec file
Merge branch 'maint'