[clang] [CIR] Recognize constant aggregate initialization of auto vars (PR #166850)

[Amr Hesham via cfe-commits]

================
@@ -265,16 +258,11 @@ void bin_comma() {
 
 // CIR: cir.func{{.*}} @_Z9bin_commav()
 // CIR:   %[[A_ADDR:.*]] = cir.alloca !rec_CompleteS, !cir.ptr<!rec_CompleteS>, ["a", init]
-// CIR:   %[[TMP_ADDR:.*]] = cir.alloca !rec_CompleteS, !cir.ptr<!rec_CompleteS>, ["agg.tmp.ensured"]
-// CIR:   %[[ZERO:.*]] = cir.const #cir.zero : !rec_CompleteS
-// CIR:   cir.store{{.*}} %[[ZERO]], %[[TMP_ADDR]] : !rec_CompleteS, !cir.ptr<!rec_CompleteS>
-// CIR:   %[[ZERO:.*]] = cir.const #cir.zero : !rec_CompleteS
-// CIR:   cir.store{{.*}} %[[ZERO]], %[[A_ADDR]] : !rec_CompleteS, !cir.ptr<!rec_CompleteS>
+// CIR:   %[[CONST:.*]] = cir.const #cir.zero : !rec_CompleteS
+// CIR:   cir.store align(4) %[[CONST]], %[[A_ADDR]] : !rec_CompleteS, !cir.ptr<!rec_CompleteS>
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AmrDeveloper wrote:

```suggestion
// CIR:   cir.store{{.*}} %[[CONST]], %[[A_ADDR]] : !rec_CompleteS, !cir.ptr<!rec_CompleteS>
```

https://github.com/llvm/llvm-project/pull/166850