fortran: wrong generic resolution when actual argument is a procedure pointer

When a generic interface has two specific procedures -- one with a
procedure-pointer dummy and one with a data-object (e.g. REAL) dummy --
gfortran incorrectly resolved calls where the actual argument was a
procedure pointer to the data-object specific, resulting in the pointer
address being interpreted as a numeric value (wrong code).

The root cause was a missing check in gfc_compare_actual_formal: the
two existing checks guard the case where the formal is a proc_pointer
or FL_PROCEDURE but the actual is not; however the reverse direction
(actual is a proc_pointer but formal is a plain data object) was not
checked.  F23:15.5.2.5, para 2 forbids this pairing.

Assisted-by: Claude Sonnet 4.6

	PR fortran/125481

gcc/fortran/ChangeLog:

	* interface.cc (gfc_compare_actual_formal): Add missing check that
	rejects a procedure-pointer actual argument corresponding to a
	data-object dummy argument (F23:15.5.2.5, para 2).  Restrict to
	EXPR_VARIABLE to avoid false positives on calls through procedure
	pointer components.

gcc/testsuite/ChangeLog:

	* gfortran.dg/generic_37.f90: New test.
	* gfortran.dg/generic_38.f90: New test.

(cherry picked from commit 7537196aef7c2a430de1064cc5922ffa2e3cabbe)