Move the Zygote off libcore.os and onto android.system.

Change-Id: Iaa20e50b05fad355bdf15bcfdc58efc9941c400c
Merge "Move the Zygote off libcore.os and onto android.system."
Remove unused import.

Change-Id: I3f6a035cda55859a7a521f3117da72ee962beb63
Merge "Remove unused import."
Fix two zygote imports.

Change-Id: I5eea2d9f48479c33e1594aaa259274e5e787a1df
Merge "Fix two zygote imports."
Merge remote-tracking branch 'aosp/master' into fml-master