[clang] [CIR] Upstream a batch of passing tests from CIR-Incubator (PR #157333)

[Burhan Söğüt via cfe-commits]

================
@@ -0,0 +1,94 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s --check-prefix=CIR
+
+void if0() {
+  int x = 0;
+
+  if constexpr (0 == 0) {
+    // CIR: cir.scope {
+    // CIR-NEXT:   %2 = cir.alloca !s32i, !cir.ptr<!s32i>, ["x", init]
+    // CIR-NEXT:   %3 = cir.const #cir.int<2> : !s32i
+    // CIR-NEXT:   cir.store %3, %2 : !s32i, !cir.ptr<!s32i>
----------------
bursot wrote:

Ben 

https://github.com/llvm/llvm-project/pull/157333