[DO NOT MERGE] Compile using Jack.

This allows to compile dex targeted java sources using Jack and Jill.
Default is still to compile with the legacy toolchain. Default can be
switched to the new toolchain by setting environement variable:
export ANDROID_COMPILE_WITH_JACK=true
Toolchain can also be forced for one module by defining
LOCAL_JACK_ENABLED:=full # disabled, full, incremental
in the mk portion defining the module.

Jack execution environement can be controlled with:

Global variable ANDROID_JACK_VM allow to change the jvm executing Jack.
Global variable ANDROID_JACK_VM_ARGS allows to change default args given
to the jvm.
Global variable ANDROID_JACK_EXTRA_ARGS allows to define some default args
to give to Jack

LOCAL_JACK_VM_ARGS allows to override default args given to the jvm for
the module.
LOCAL_JACK_EXTRA_ARGS allows to override default args passed to Jack.

This includes cherry-picks of the following changes:
b4c49cba
22c3fa6d
138768c1
5dd3e1d3
83d5d040
8bc90fd2
14027470
0fbc9ff2
833b427d
f9a27f45
28096669
37822c44
c6b44d43
d2a76c14
06744f60
95573d50
b8213916
2794e7b5
801f2c44
c76d99dc
f528e132
76a5e0bd
e25b3984 Partially, only Jack related parts werekept
ec46a3b7
abee3a9f
77cbe10f
daf07db4
b6bfb589

Ie all Jack related changes untill
b6bfb589
except
a96cc59a "Use Jack by default"

Change-Id: If9d47ef1c4fd1e6765ad2a47d816c1ad3cfab0e3