Add CTS for creating keepalive offloads on cellular

Bug: 134352656
Test: atest android.net.cts.ConnectivityManagerTest (--instant)
Merged-In: Ia7b1111abe687efad032a8c9205990c97a769fcd
Change-Id: Ib6b01356d785c5b7684520eef9f9d1fe48187582
(cherry picked from commit 8550488c7cf0c0ab2af06189aca5ad50c39e5276)
1 file changed
tree: 1c72528f6987db72e7d7e148f258c25001cd1e82
  1. tests/