Implement the get_locations RA method in JavaHL.

[in subversion/bindings/javahl/src/org/apache/subversion/javahl]
* ISVNRemote.java, remote/RemoteSession.java
  (ISVNRemote.getLocations): New method.

[in subversion/bindings/javahl/native]
* RemoteSession.h (RemoteSession::getLocations): New method.
* RemoteSession.cpp (long_iterable_to_revnum_array, location_hash_to_map):
   New private helper functions.
  (RemoteSession::getLocations): Implement.

[in subversion/bindings/javahl/tests/org/apache/subversion/javahl]
* SVNRemoteTests.java (SVNRemoteTests.testGetLocations): New test case.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1507164 13f79535-47bb-0310-9956-ffa450edef68