Add failing test

Author: jakebailey

tests/cases/fourslash/parserCorruptionAfterMapInClass.ts

@@ -0,0 +1,17 @@
+/// <reference path="fourslash.ts" />
+
+// @target: esnext
+// @lib: es2015
+// @strict: true
+
+//// class C {
+////     map = new Set<string, number>/*$*/
+////
+////     foo() {
+////
+////     }
+//// }
+
+goTo.marker('$');
+edit.insert('()');
+verify.getSyntacticDiagnostics([]);