Add Windows build and unit test to test-patch pre-commit testing

The "test-patch" utility is triggered by "Patch Available" state in Jira, and runs nine different sets of builds, tests, and static analysis tools. Currently only the Linux environment is tested. Need to add tests for Java build under Windows, and unit test execution under Windows.

At this time, the community has decided that "-1" on these new additional tests shall not block commits to the code base. However, contributors and code reviewers are encouraged to utilize the information provided by these tests to help keep Hadoop cross-platform compatible. Modify http://wiki.apache.org/hadoop/HowToContribute to document this.