Added test for completions at beginning of file.

tests/cases/fourslash/completionListAtBeginningOfFile01.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+/////*1*/
+////var x = 0, y = 1, z = 2;
+////enum E {
+////    A, B, C
+////}
+
+goTo.marker("1");
+verify.completionListContains("x");
+verify.completionListContains("y");
+verify.completionListContains("z");
+verify.completionListContains("E");