[os_mon] Quote path to programs run with open_port({spawn,...

This is to allow space in the path.
Convert command string to encoded binary in heart:set_cmd/1

OTP-10843

In order to allow unicode filenames in heart commands, the command
string is now encoded according to the file name translation mode of
the emulator (file:native_name_encoding()) before it is sent to the
heart process.
[sasl] Quote path to program run with open_port({spawn,...

This is to allow space in the path.
Quote path to erl executable in slave to allow space in path
[test_server] Quote path to erl executable when starting slave nodes

This is to allow space in path.
[sasl] In test, quote erlsrv executable in call to open_port/2
[sasl] Write erl.ini as utf8, allowing unicode path for root dir and bin dir
[sasl] Update example/target_system.erl to handle unicode

This example module can now create and install a release in a
directory which contains unicode characters. The erlang node must be
started with the +fnu* switch for this work.
[sasl] Rewrite release_handler_SUITE:clean_priv_dir to work on unicode paths

This function used os:cmd("rm -rf " ++ File), and it failed when the
file path contained characters > 255. The function now uses
file:delete/1 and file:del_dir/1 instead.
[sasl] Update tests to run under unicode path

In order to test that unicode paths can be used in release handling,
the release_handler_SUITE will use a priv_dir with unicode characters
if the file name translation mode is utf8 (not on windows).
[reltool] Write erl.ini as UTF-8

Since file names on windows are unicode, and erl.ini contains paths to
'Bindir' and 'Rootdir', this file is now encoded in UTF-8.
[sasl] Use unicode characters in priv dir name also on windows
[reltool] Use unicode characters in work dir for unicode test
Merge branch 'maint'
Merge branch 'maint'
Merge branch 'maint'

* maint:
  Only verify not busy for erlang:send(Port, Msg, [nosuspend]) until scheduled
  Make high_msgq_watermark and low_msgq_watermark generic inet options
  Do not treat port_set_data/port_get_data as signals
  Add 'frmptr' emulator type

Conflicts:
	erts/preloaded/ebin/erlang.beam
	erts/preloaded/ebin/erts_internal.beam
	erts/preloaded/ebin/prim_inet.beam
Merge branch 'maint'

* maint:
  [stdlib] Fix pretty printing of invalid forms
Merge branch 'maint'
Merge branch 'maint'
erts: Windows, use widechars for all paths during startup

To enable unicode paths as installation dir and allow
unicode in arguments