Fortran: Simplify len_trim with array ref and fix mapping bug[PR84868].

Fortran: Simplify len_trim with array ref and fix mapping bug[PR84868].

2024-07-16  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/84868
	* simplify.cc (gfc_simplify_len_trim): If the argument is an
	element of a parameter array, simplify all the elements and
	build a new parameter array to hold the result, after checking
	that it doesn't already exist.
	* trans-expr.cc (gfc_get_interface_mapping_array) if a string
	length is available, use it for the typespec.
	(gfc_add_interface_mapping): Supply the se string length.

gcc/testsuite/
	PR fortran/84868
	* gfortran.dg/pr84868.f90: New test.