The libraries need to build as system_current since they will be used in
modules that should build against that SDK.
As notable changes, NetworkFactory stops using a common BASE for
handler messages, as no message ID is shared with other handlers (all
public messages numbers are for receiving only). It also indexes
NetworkRequests by using the request itself in the request table; this
is fine because .equals() / .hashCode() are implemented properly, and
no request can be used that has the same ID but differences in other
members.
Test: built, flashed, WiFi and telephony working
Test: atest FrameworksNetTests FrameworksWifiTests \
FrameworksTelephonyTests
Bug: 138306002
Merged-In: I2ea2be0039b67ba34fc26e62bdb839ab7d42300c
Change-Id: I2ea2be0039b67ba34fc26e62bdb839ab7d42300c
(clean cherry-pick from internal branch)
ce241a3b79