tests: java: factor the definition of Position

* tests/local.at (AT_JAVA_POSITION_DEFINE): New.
* tests/java.at, tests/javapush.at: Use it.

tests/java.at

@@ -158,43 +158,7 @@ AT_LOCATION_IF([[
 };
 %%]], [[
 }]])[
-
-class Position {
-  public int line;
-  public int token;
-
-  public Position ()
-  {
-    line = 0;
-    token = 0;
-  }
-
-  public Position (int l, int t)
-  {
-    line = l;
-    token = t;
-  }
-
-  public boolean equals (Position l)
-  {
-    return l.line == line && l.token == token;
-  }
-
-  public String toString ()
-  {
-    return Integer.toString (line) + "." + Integer.toString(token);
-  }
-
-  public int lineno ()
-  {
-    return line;
-  }
-
-  public int token ()
-  {
-    return token;
-  }
-}
+]AT_JAVA_POSITION_DEFINE[
 ]])
 
 AT_BISON_OPTION_POPDEFS