middle-end/105461 - opts processing of -fvar-tracking

The flag_var_tracking reset in finish_options doesn't match the
condition in process_options, in particular we fail to reset it
when the option was specified on the command line.  The following
fixes this and also alters the debug info level guard to match
the one in process_options.

2022-05-03  Richard Biener  <rguenther@suse.de>

	PR middle-end/105461
	* opts.cc (finish_options): Match the condition to
	disable flag_var_tracking to that of process_options.

	* gcc.dg/pr105461.c: New testcase.