Added named import to definitions test

This makes the test slightly more thorough.

Author: owen-mc

go/ql/test/query-tests/definitions/definitions.expected

@@ -1,3 +1,4 @@
+| greet.go:6:2:6:6 | myfmt | greet.go:3:8:3:12 | myfmt | V |
 | main.go:6:26:6:28 | who | main.go:5:12:5:14 | who | V |
 | main.go:11:2:11:6 | greet | main.go:5:6:5:10 | greet | V |
 | main.go:11:8:11:12 | world | main.go:10:2:10:6 | world | V |

go/ql/test/query-tests/definitions/greet.go

@@ -1,7 +1,7 @@
 package main
 
-import "fmt"
+import myfmt "fmt"
 
 func greet2() {
-	fmt.Println("Hello world!")
+	myfmt.Println("Hello world!")
 }