[Flang][OpenMP] : Compilation error involving Fortran pointers and data-sharing attributes

Issue description:
	When DEFAULT DSA is NONE, all data refs must be listed in one of the data sharing clause.
	But when a Cray pointer is listed in one of the data sharing clause, Cray pointee can be used in parallel region.
	This is valid as per standard.
	"Cray pointees have the same data-sharing attribute as the storage with which their Cray pointers are associated."

Solution:
	Added a check to discard checking Cray pointee when DEFAULT DSA is NONE.

This patch has code changes and a test case.

Author: kiranktp

flang/lib/Semantics/resolve-directives.cpp

@@ -1995,7 +1995,9 @@ void OmpAttributeVisitor::Post(const parser::Name &name) {
             // Exclude indices of sequential loops that are privatised in
             // the scope of the parallel region, and not in this scope.
             // TODO: check whether this should be caught in IsObjectWithDSA
-            !symbol->test(Symbol::Flag::OmpPrivate)) {
+            !symbol->test(Symbol::Flag::OmpPrivate) &&
+            // If the symbol is a CrayPointee, It cannot appear in DSA clause
+            !symbol->test(Symbol::Flag::CrayPointee)) {
           context_.Say(name.source,
               "The DEFAULT(NONE) clause requires that '%s' must be listed in "
               "a data-sharing attribute clause"_err_en_US,

flang/test/Semantics/OpenMP/cray-pointer-usage.f90

@@ -0,0 +1,17 @@
+!RUN: %python %S/../test_errors.py %s %flang -fopenmp
+subroutine test_crayptr
+  implicit none
+  integer :: I
+  real*8 var(*)
+  pointer(ivar,var)
+  real*8 pointee(8)
+
+  pointee(1) = 42.0
+  ivar = loc(pointee)
+
+  !$omp parallel num_threads(2) default(none) shared(ivar)
+    print *, var(1)
+  !$omp end parallel
+
+end subroutine test_crayptr
+