[llvm] [UTC] Support to test annotated IR (PR #165419)

[Kunqiu Chen via llvm-commits]

================
@@ -13,34 +13,41 @@ define i32 @main() {
 ; CHECK-LABEL: @main(
 ; CHECK-NEXT:    store i32 6, ptr @e, align 4
 ; CHECK-NEXT:    br label [[TMP1:%.*]]
-; CHECK:         [[TMP2:%.*]] = load i32, ptr @d, align 4
+; CHECK:       1:
----------------
Camsyn wrote:

Actually, it works. The change here is adding a check for block labels.
From
```
; CHECK:         [[TMP2:%.*]] = load i32, ptr @d, align  4
```
To
```
; CHECK:       1:
; CHECK-NEXT:    [[TMP2:%.*]] = load i32, ptr @d, align 4
```

https://github.com/llvm/llvm-project/pull/165419