Add jdk8 synthetics case

Example case for https://github.com/infradna/bridge-method-injector/issues/4

    javap injector/target/test-classes/synthetics/B.class 

outputs

```
public class B extends A {
  public B();
  public java.lang.CharSequence getProperty();
  public java.lang.Object getProperty();
  public java.lang.String getProperty();
  public java.lang.String getProperty();
}
```

on jdk7

```
public class B extends A {
  public B();
  public java.lang.CharSequence getProperty();
  public java.lang.Object getProperty();
  public java.lang.String getProperty();
}
```