Fix Coarray in associate not a coarray. [PR110033]

Fix Coarray in associate not a coarray. [PR110033]

A coarray used in an associate did not become a coarray in the block of
the associate.  This patch fixes that and the same also in select type
statements.

	PR fortran/110033

gcc/fortran/ChangeLog:

	* class.cc (gfc_is_class_scalar_expr): Coarray refs that ref
	only self, aka this image, are regarded as scalar, too.
	* resolve.cc (resolve_assoc_var): Ignore this image coarray refs
	and do not build a new class type.
	* trans-expr.cc (gfc_get_caf_token_offset): Get the caf token
	from the descriptor for associated variables.
	(gfc_conv_variable): Same.
	(gfc_trans_pointer_assignment): Assign token to temporary
	associate variable, too.
	(gfc_trans_scalar_assign): Add flag that assign is for associate
	and use it to assign the token.
	(is_assoc_assign): Detect that expressions are for associate
	assign.
	(gfc_trans_assignment_1): Treat associate assigns like pointer
	assignments where possible.
	* trans-stmt.cc (trans_associate_var): Set same_class only for
	class-targets.
	* trans.h (gfc_trans_scalar_assign): Add flag to
	trans_scalar_assign for marking associate assignments.

gcc/testsuite/ChangeLog:

	* gfortran.dg/coarray/associate_1.f90: New test.