[Bug] Duplicated class simple name in import section when use inline class qualified name

**Describe the bug**
When source code use inline qualified name in a class, and two of them have the same simple name, the classes imported will be conflict.

**To Reproduce**

Input:
```java
String code1 = "package io.example.pack1;\n" +
"import io.example.pack2.Class1;\n" +
" public class Example{\n" +
" void add(Class1 value){\n" +
" io.example.pack4.Class1 class1 = null;\n" +
" io.example.pack.Class1 class2 = null;\n" +
" }\n" +
" }\n";
CtClass class1 = Launcher.parseClass(code1);
System.out.println(class1.toStringWithImports());
```

Output:
```java
package io.example.pack1;
import io.example.pack.Class1;
import io.example.pack2.Class1;
import io.example.pack3.Class1;
import io.example.pack4.Class1;
public class Example {
void add(Class1 value) {
Class1 class1 = null;
Class1 class2 = null;
}
}
```

Test case pull request: https://github.com/INRIA/spoon/pull/4785

This problem doesn't only happen when parsing class, but also happened in the output file. You can check it in the test case in the pull request.

**Operating system, JDK and Spoon version used**

* OS: MacOS
* JDK: Java 11
* Spoon version: 10.1.1

Reproduce the example with Launcher.parseClass and inspect the output from CtClass.toStringWithImports. Review the test case in pull request #4785, including its output-file coverage. Done means the generated imports and references remain unambiguous when qualified names share the same simple class name.

Written by the indexing model from the issue text.