[openacc] Allow async, wait and device_type on the data construct

[clementval]

Summary

From OpenACC 3.2 specification:
The async, wait, and device_type clauses may be specified on data
constructs.

This patch adds these clauses in the ACC.td file and adds some tests
for them in flang parsing.

[razvanlupusoru]

Looks great.

flang/test/Semantics/OpenACC/acc-data.f90

program openacc_data_validity
   !ERROR: At most one IF clause can appear on the DATA directive
   !$acc data copy(aa) if(.true.) if(ifCondition)
   !$acc end data
 
   !$acc data copyin(i)
   !ERROR: Unmatched PARALLEL directive
   !$acc end parallel
 
+  !$acc data copy(aa) async
+  !$acc end data
+
+  !$acc data copy(aa) wait
+  !$acc end data
+
+  !$acc data copy(aa) device_type(1) wait
+  !$acc end data
+
 end program openacc_data_validity

llvm/include/llvm/Frontend/OpenACC/ACC.td

 //===----------------------------------------------------------------------===//
 
 // 2.12
 def ACC_Atomic : Directive<"atomic"> {}
 
 // 2.6.5
 def ACC_Data : Directive<"data"> {
   let allowedOnceClauses = [
+    VersionedClause<ACCC_Async, 32>,
     VersionedClause<ACCC_If>,
     VersionedClause<ACCC_Default>
   ];
+  let allowedClauses = [
+    VersionedClause<ACCC_DeviceType, 32>,
+    VersionedClause<ACCC_Wait, 32>
+  ];
   let requiredClauses = [
     VersionedClause<ACCC_Attach>,
     VersionedClause<ACCC_Copy>,
     VersionedClause<ACCC_Copyin>,
     VersionedClause<ACCC_Copyout>,
     VersionedClause<ACCC_Create>,
     VersionedClause<ACCC_Default>,
     VersionedClause<ACCC_DevicePtr>,