Merge "bpfmap: Move to Common Location"

Tethering/Android.bp

...stack/tethering/apishim/api31/BpfCoordinatorShimImpl.java

Tethering/jni/com_android_networkstack_tethering_BpfMap.cpp

Tethering/jni/onload.cpp

Tethering/proguard.flags

...rc/com/android/networkstack/tethering/BpfCoordinator.java

Tethering/src/com/android/networkstack/tethering/BpfMap.java

...ed/src/com/android/networkstack/tethering/BpfMapTest.java

Tethering/tests/unit/src/android/net/ip/IpServerTest.java

...om/android/networkstack/tethering/BpfCoordinatorTest.java