[DSE] Remove some dead code from DSE tests.

Some tests depend on DSE removing dead instructions unrelated to any
memory optimization. That's not really DSE's job, remove it.

Author: fhahn

llvm/test/Transforms/DeadStoreElimination/memintrinsics.ll

@@ -38,7 +38,6 @@ define void @test3() {
 ; CHECK-NEXT:    ret void
 ;
   %A = alloca i8
-  %B = alloca i8
 
   store i8 0, i8* %A  ;; Written to by memset
 
@@ -87,7 +86,6 @@ define void @test6() {
 ; CHECK-NEXT:    ret void
 ;
   %A = alloca i16, i16 1024, align 2
-  %B = alloca i16, i16 1024, align 2
 
   store atomic i16 0, i16* %A unordered, align 2 ;; Written to by memset
 

llvm/test/Transforms/DeadStoreElimination/merge-stores-big-endian.ll

@@ -40,7 +40,6 @@ entry:
 
   %wptr = bitcast i64* %ptr to i16*
   %wptr1 = getelementptr inbounds i16, i16* %wptr, i64 1
-  %wptr2 = getelementptr inbounds i16, i16* %wptr, i64 2
   %wptr3 = getelementptr inbounds i16, i16* %wptr, i64 3
 
   ;; We should be able to merge these two stores with the i64 one above

llvm/test/Transforms/DeadStoreElimination/merge-stores.ll

@@ -39,7 +39,6 @@ entry:
 
   %wptr = bitcast i64* %ptr to i16*
   %wptr1 = getelementptr inbounds i16, i16* %wptr, i64 1
-  %wptr2 = getelementptr inbounds i16, i16* %wptr, i64 2
   %wptr3 = getelementptr inbounds i16, i16* %wptr, i64 3
 
   ;; We should be able to merge these two stores with the i64 one above