Fortran: Fix deferred character lengths in array constructors [PR93833].

Fortran: Fix deferred character lengths in array constructors [PR93833].

2020-12-29  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/93833
	* trans-array.c (get_array_ctor_var_strlen): If the character
	length backend_decl cannot be found, convert the expression and
	use the string length. Clear up some minor white space issues
	in the rest of the file.

gcc/testsuite/
	PR fortran/93833
	* gfortran.dg/deferred_character_36.f90 : New test.

(cherry picked from commit feae0af82753e06fbff6103da5fbb3b28e1ddbd7)