Fortran: Assign allocated caf-memory to scalar members [PR84870]

Allocating a coarray required an array-descriptor.  For scalars a
temporary descriptor was created.  Assigning the allocated memory from
the temporary descriptor back to the scalar is now added.

gcc/fortran/ChangeLog:

	PR fortran/84870

	* trans-array.cc (duplicate_allocatable_coarray): For scalar
	allocatable components the memory allocated is now assigned to
	the component's pointer.

gcc/testsuite/ChangeLog:

	* gfortran.dg/coarray/alloc_comp_10.f90: New test.