[CIR][NFC] remove redundant test in CIR/IR/data-member-ptr.cir (#582)

As suggested in #401, this PR removes the `get_global_member` test in
`CIR/IR/data-member-ptr.cir` as it is redundant.

The original comment:
#401 (comment)

clang/test/CIR/IR/data-member-ptr.cir

@@ -3,8 +3,6 @@
 !s32i = !cir.int<s, 32>
 !ty_22Foo22 = !cir.struct<struct "Foo" {!s32i}>
 
-#global_ptr = #cir.data_member<0> : !cir.data_member<!s32i in !ty_22Foo22>
-
 module {
   cir.func @null_member() {
     %0 = cir.const #cir.data_member<null> : !cir.data_member<!s32i in !ty_22Foo22>
@@ -16,12 +14,6 @@ module {
     %1 = cir.get_runtime_member %arg0[%0 : !cir.data_member<!s32i in !ty_22Foo22>] : !cir.ptr<!ty_22Foo22> -> !cir.ptr<!s32i>
     cir.return
   }
-
-  cir.func @get_global_member(%arg0: !cir.ptr<!ty_22Foo22>) {
-    %0 = cir.const #global_ptr
-    %1 = cir.get_runtime_member %arg0[%0 : !cir.data_member<!s32i in !ty_22Foo22>] : !cir.ptr<!ty_22Foo22> -> !cir.ptr<!s32i>
-    cir.return
-  }
 }
 
 //      CHECK: module {
@@ -37,10 +29,4 @@ module {
 // CHECK-NEXT:      cir.return
 // CHECK-NEXT:   }
 
-// CHECK-NEXT:   cir.func @get_global_member(%arg0: !cir.ptr<!ty_22Foo22>) {
-// CHECK-NEXT:     %0 = cir.const #cir.data_member<0> : !cir.data_member<!s32i in !ty_22Foo22>
-// CHECK-NEXT:     %1 = cir.get_runtime_member %arg0[%0 : !cir.data_member<!s32i in !ty_22Foo22>] : !cir.ptr<!ty_22Foo22> -> !cir.ptr<!s32i>
-// CHECK-NEXT:     cir.return
-// CHECK-NEXT:   }
-
 //      CHECK: }