[OpenMP, test] Fix use of undef DECL FileCheck var

[thopre]

Summary

OpenMP test target_data_use_device_ptr_if_codegen contains a CHECK-NOT
directive using an undefined DECL FileCheck variable. It seems copied
from target_data_use_device_ptr_codegen where there's a CHECK for a load
that defined the variable. Since there is no corresponding load in this
testcase, the simplest is to simply forbid any store and get rid of the
variable altogether.

[ABataev]

LG, thanks

clang/test/OpenMP/target_data_use_device_ptr_if_codegen.cpp

 
 void add_one(float *b, int dm)
 {
   // CK1:     [[BP:%.+]] = getelementptr inbounds [1 x i8*], [1 x i8*]* %{{.+}}, i32 0, i32 0
   // CK1:     [[CBP:%.+]] = bitcast i8** [[BP]] to float**
   // CK1:     store float* [[B_ADDR:%.+]], float** [[CBP]]
   // CK1:     call void @__tgt_target_data_begin{{.+}}[[MTYPE00]]
   // CK1:     [[VAL:%.+]] = load float*, float** [[CBP]],
-  // CK1-NOT: store float* [[VAL]], float** [[DECL]],
+  // CK1-NOT: store float* [[VAL]], float** {{%.+}},
   // CK1:     store float* [[VAL]], float** [[PVT:%.+]],
   // CK1:     [[TT:%.+]] = load float*, float** [[PVT]],
   // CK1:     call i32 @__tgt_target{{.+}}[[MTYPE01]]
   // CK1:     call i32 @__tgt_target{{.+}}[[MTYPE02]]
   // CK1:     call void @__tgt_target_data_end{{.+}}[[MTYPE00]]
 #pragma omp target data map(tofrom:b[:1]) use_device_ptr(b) if(dm == 0)
   {
 #pragma omp target is_device_ptr(b)
   {
     b[0] += 1;
   }
   }
 }
 
 #endif
 #endif