Fortran: Handle allocated() with coindexed scalars [PR93834]

Fortran: Handle allocated() with coindexed scalars [PR93834]

While for an allocatable 'array', 'array(:)' and 'array(:)[1]' are
not allocatable, it is believed that not only 'scalar' but also
'scalar[1]' is allocatable.  However, coarrays are collectively
established/allocated; thus, 'allocated(scalar[i])' is equivalent
to 'allocated(scalar)'. [At least when assuming that 'i' does not
refer to a failed image.]

2021-09-23  Harald Anlauf  <anlauf@gmx.de>
	    Tobias Burnus  <tobias@codesourcery.com>

	PR fortran/93834
gcc/fortran/ChangeLog:

	* trans-intrinsic.c (gfc_conv_allocated): Cleanup. Handle
	coindexed scalar coarrays.

gcc/testsuite/ChangeLog:

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