Deleting nondeterministic test.

The test basically dereferences unsafe pointer in an async method where the original stack could be long gone. That results in undefined and unsafe behavior.

Fixes #7334

src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenAsyncTests.cs

@@ -1920,73 +1920,6 @@ static void Main()
             CompileAndVerify(source, "0");
         }
 
-        [Fact(Skip= "https://github.com/dotnet/roslyn/issues/7334")]
-        public void Return07_2()
-        {
-            var source = @"
-using System;
-using System.Threading;
-using System.Threading.Tasks;
-
-class TestCase
-{
-    unsafe struct S
-    {
-        public int value;
-        public S* next;
-    }
-
-    public async void Run()
-    {
-        int test = 0;
-        int result = 0;
-        Func<Task<dynamic>> func, func2 = null;
-
-        try
-        {
-            test++;
-            S s = new S();
-            S s1 = new S();
-            unsafe
-            {
-                S* head = &s;
-                s.next = &s1;
-                func = async () => { (*(head->next)).value = 1; result++; return head->next->value; };
-                func2 = async () => (*(head->next));
-            }
-
-            var x = await func();
-            if (x != 1)
-                result--;
-            var xx = await func2();
-            if (xx.value != 1)
-                result--;
-        }
-        finally
-        {
-            Driver.Result = test - result;
-            Driver.CompleteSignal.Set();
-        }
-    }
-}
-
-class Driver
-{
-    static public AutoResetEvent CompleteSignal = new AutoResetEvent(false);
-    public static int Result = -1;
-    public static void Main()
-    {
-        TestCase tc = new TestCase();
-        tc.Run();
-        CompleteSignal.WaitOne();
-
-        Console.WriteLine(Result);
-    }
-}";
-            var options = new CSharpCompilationOptions(OutputKind.ConsoleApplication, allowUnsafe: true);
-            CompileAndVerify(source, "0", options: options);
-        }
-
         [Fact]
         [WorkItem(625282, "DevDiv")]
         public void Generic05()