Add 'global' driver option to erl_ddll:try_load/3

On systems using dlopen() to load a driver, it may be necessary
to use the RTLD_GLOBAL flag.

This patch adds support for the 'global' atom in 'driver_options'
Using {driver_options, [global]} will set the RTLD_FLAG.

Parts of erts using dlopen() unrelated to try_load/3 have been
modified to use only RTLD_NOW, as it is the current behaviour.

This option will be ignored on platforms without dlopen().
Add test cases
Add missing RTLD_GLOBAL definition
Merge branch 'dg/win_icon' into pu
Merge branch 'sk/odbc64' into pu
Merge branch 'rc/break-out-asserts' into pu
Merge branch 'pn/error-logger-sup_handler' into pu
Merge branch 'ks/hipe-cleanup' into pu
Merge branch 'ks/hipe-cleanup-escaping' into pu
Merge branch 'ks/erlang-spawn_opt-process_level' into pu
Merge branch 'nox/compile-column-numbers' into pu
Merge branch 'nox/fix-ssh-html-doc' into pu
Merge branch 'nox/rm-reverse-eta-conversion/OTP-10682' into pu
Merge branch 'hm/reltool_relaxed_exclude' into pu
Merge branch 'og/erl_ddll_try_load3' into pu
Merge branch 'fredrik/update_preloaded' into pu