Split up testJavaWithEnvFs

Instead of passing all the options to testJavaWithEnvFs, split it
up into testConfig, testContext, and run.  Tests that don't need
any special options can continue to use testJava, more complicated
tests can call the three functions manually.  This gives more
flexibility in complicated tests for the next patch.

Test: soong java tests
Change-Id: Ifd5dcb40cf08e4cbf69bf8e02c5698adbfbcdcb3