Fortran: Unify gfc_get_location handling; fix expr->ts bug

Fortran: Unify gfc_get_location handling; fix expr->ts bug

This commit reduces code duplication by moving gfc_get_location
from trans.cc to error.cc.  The gcc_assert is now used more often
and reveald a bug in gfc_match_array_constructor where the union
expr->ts.u.derived of a derived type is partially overwritten by
the assignment expr->ts.u.cl->... as a ts.type == BT_CHARACTER check
was missing.

gcc/fortran/ChangeLog:

	* array.cc (gfc_match_array_constructor): Only update the
	character length if the expression is of character type.
	* error.cc (gfc_get_location_with_offset): New; split off
	from ...
	(gfc_format_decoder): ... here; call it.
	* gfortran.h (gfc_get_location_with_offset): New prototype.
	(gfc_get_location): New inline function.
	* trans.cc (gfc_get_location): Remove function definition.
	* trans.h (gfc_get_location): Remove declaration.