Fix observer application crash

When clicking an HTML-link to a port before the port tab has been opened for the first time, observer would crash since port info is not initiated. This is now corrected.

Also, when clicking on an HTML link to a port, and the port does not exist,
then pop up an info dialog saying "No such port". 

OTP-14151

If a crashdump is truncated due to size limit reached, a new 'abort'
tag with reason is added at the end of the crashdump. This reason is
now displayed along with the truncated-warning.

* siri/observer/improve-trace/OTP-13481:
  [observer] Update user guide
  [observer] Automatically add active node
  [observer] Allow more trace flags on procs/ports from GUI
  [runtime_tools] Don't trace the trace client port
  [runtime_tools] Allow setting trace flag 'exiting' with dbg
  [observer] Add more default match specs for messages
  [observer] Add test of new Ports tab
  [observer] Improve appearance in Trace tab
  [observer] Allow multiple select in Ports tab
  [observer] Make right click menu act on the "expected pid"
  [observer] In Trace tab, show procs/ports for selected node only
  [observer] Add right click menu in Table tab
  [observer] Add menu option to set default MS for send/receive
  [observer] Add tracing of ports
  [ttb] Allow setting trace flags on ports
  [observer] Set correct parent in Label dialog
  [observer] Add Ports tab in GUI
  [observer] Add functionality in GUI for trace pattern on messages
  [ttb] Set trace patterns on messages

Conflicts:
	lib/observer/src/observer_wx.erl

Tests on slow vnc server times out.

* siri/cuddle-master:
  Extend timer in test
  Update crashdump_viewer_SUITE with new release numbers
  Set longer timetrap when creating dsa files
  Check that ssh application exists before starting netconf tests
  Improve error control when starting ssh in netconf test

After bumping to Erlang/OTP 19, R16 dumps can no longer be
created. Now we test dumps from OTP 17 and 18.