[Matrix] Add align info to some more loads/stores (NFC).

Some tests were missing alignment info. Subsequent changes properly
preserve the set alignment. Set it properly beforehand, to avoid
unnecessary test changes.

llvm/test/Transforms/LowerMatrixIntrinsics/multiply-fused-multiple-blocks.ll

@@ -284,12 +284,12 @@ entry:
 
 true:
   %a.add = fadd <6 x double> %a, %a
-  store <6 x double> %a.add, <6 x double>* %A
+  store <6 x double> %a.add, <6 x double>* %A, align 8
   br label %end
 
 false:
   %b.add = fadd <6 x double> %b, %b
-  store <6 x double> %b.add, <6 x double>* %B
+  store <6 x double> %b.add, <6 x double>* %B, align 8
   br label %end
 
 end:

llvm/test/Transforms/LowerMatrixIntrinsics/propagate-forward.ll

@@ -37,7 +37,7 @@ define void @transpose_store(<8 x double> %a, <8 x double>* %Ptr) {
 ;
 entry:
   %c  = call <8 x double> @llvm.matrix.transpose(<8 x double> %a, i32 2, i32 4)
-  store <8 x double> %c, <8 x double>* %Ptr
+  store <8 x double> %c, <8 x double>* %Ptr, align 8
   ret void
 }
 

llvm/test/Transforms/LowerMatrixIntrinsics/propagate-mixed-users.ll

@@ -43,7 +43,7 @@ define <8 x double> @strided_load_4x4(<8 x double> %in, <8 x double>* %Ptr) {
 ; CHECK-NEXT:    ret <8 x double> [[TMP19]]
 ;
   %transposed = call <8 x double> @llvm.matrix.transpose(<8 x double> %in, i32 4, i32 2)
-  store <8 x double> %transposed, <8 x double>* %Ptr
+  store <8 x double> %transposed, <8 x double>* %Ptr, align 8
   call void @foo(<8 x double> %transposed)
   ret <8 x double> %transposed
 }