C#: Add inline array test to expressions.

csharp/ql/test/library-tests/expressions/expressions.cs

@@ -85,7 +85,8 @@ namespace Expressions
             other[i, Nested.constant] = this[0, ""]; // indexer write and read access, and access to constant through static type reference
             int[] array = { (int)4ul, (int)3l }; // array creation
             array[1] = 5; // array element access
-
+            MyInlineArray inlinearray = new MyInlineArray();
+            inlinearray[2] = 7; // inline array element access
         }
 
         void MainIsAsCast(string s, object o, object p)
@@ -507,4 +508,10 @@ namespace Expressions
             var y = typeof((bool, int[], dynamic));
         }
     }
+
+    [System.Runtime.CompilerServices.InlineArray(10)]
+    struct MyInlineArray
+    {
+        private int myInlineArrayElements;
+    }
 }