[Android] Implement onPageLoadStopped with LoadStatus parameter

Previously, the LoadStatus of onPageLoadStopped is always FINISHED.
Implement it by record the load status when stopLoading() and
onErrorReceived() get called.

BUG=https://crosswalk-project.org/jira/browse/XWALK-2031
Merge pull request #2167 from wang16/load_status

[Android] Implement onPageLoadStopped with LoadStatus parameter