Can't use `java.util.List` object after importing `java.awt.List`

[kishida naoki]

We can' t use `java.util.List` object after importing `java.awt.List`
I mean that JShell behaves strangely when we have two same named classes
from different packages.

The below is run on JDK 14 ea 36

```
$ jshell
|  Welcome to JShell -- Version 14
|  For an introduction type: /help intro

jshell> var a = List.of("aa")
a ==> [aa]

jshell> a
a ==> [aa]

jshell> import java.awt.List

jshell> a
|  Error:
|  cannot find symbol
|    symbol:   variable a
|  a
|  ^

jshell> var b = java.util.List.of("bb")
|  Error:
|  type java.awt.List does not take parameters
|  var b = java.util.List.of("bb");
|  ^----------^
```

-- 
Naoki Kishida