[test] Add test case for rdar://133460404

Author: hamishknight

test/IDE/complete_rdar133460404.swift

@@ -0,0 +1,11 @@
+// RUN: %batch-code-completion
+
+// rdar://133460404 - Make sure we complete for the rebound local variable.
+func bar() {
+  var foo: Int?
+  if let foo = foo {
+    let foo = ""
+    #^COMPLETE^#
+  }
+}
+// COMPLETE: Decl[LocalVar]/Local: foo[#String#]; name=foo