Add test for sequence point for deconstruction (#21809)

src/Compilers/CSharp/Test/Emit/PDB/PDBTests.cs

@@ -6861,6 +6861,52 @@ public void SyntaxOffset_TupleDeconstruction()
 </symbols>");
         }
 
+        [Fact]
+        public void TestDeconstruction()
+        {
+            var source = @"
+public class C
+{
+    public static (int, int) F() => (1, 2);
+
+    public static void Main()
+    {
+        int x, y;
+        (x, y) = F();
+        System.Console.WriteLine(x + y);
+    }
+}
+";
+            var c = CreateStandardCompilation(source, new[] { ValueTupleRef, SystemRuntimeFacadeRef }, options: TestOptions.DebugDll);
+            var v = CompileAndVerify(c);
+
+            v.VerifyIL("C.Main", @"
+{
+  // Code size       29 (0x1d)
+  .maxstack  2
+  .locals init (int V_0, //x
+                int V_1) //y
+  // sequence point: {
+  IL_0000:  nop
+  // sequence point: (x, y) = F();
+  IL_0001:  call       ""(int, int) C.F()""
+  IL_0006:  dup
+  IL_0007:  ldfld      ""int System.ValueTuple<int, int>.Item1""
+  IL_000c:  stloc.0
+  IL_000d:  ldfld      ""int System.ValueTuple<int, int>.Item2""
+  IL_0012:  stloc.1
+  // sequence point: System.Console.WriteLine(x + y);
+  IL_0013:  ldloc.0
+  IL_0014:  ldloc.1
+  IL_0015:  add
+  IL_0016:  call       ""void System.Console.WriteLine(int)""
+  IL_001b:  nop
+  // sequence point: }
+  IL_001c:  ret
+}
+", sequencePoints: "C.Main", source: source);
+        }
+
         [Fact]
         public void SyntaxOffset_TupleParenthesized()
         {