Test: m clean && m -j java and java_test.go

Change-Id: I110a0ff029448d3319aed2788d25d90a6c1a7fa0

Test: None
Change-Id: Ie2ad921974dc4ff82a3c6308736830cacfebf806

filegroup is a module that contains a list of files, and can be used
to export files across package boundaries.  filegroups (and genrules)
can be referenced from srcs properties of other modules using the
syntax ":module".

Test: m -j
Change-Id: I3d6fc4819c0b4225b474e0ad42f0d947f55a5961

Use go/Android.bp link, add a little more on androidmk conversions.

Test: none
Change-Id: Ibe2be4ad54b6d9a8954d7efbb40d04dc54c8dbf2

Change-Id: I07970cddefb981f6708b276ac5b04d311d1843d9