[SM15.2] Remove loop when generating traffic over data connection This is not needed, since the issue in StatsPullAtomService is fixed in counter-part change. Test: atest android.cts.statsd.atom.UidAtomTests#testMobileBytesTransfer Test: atest android.cts.statsd.atom.UidAtomTests#testMobileBytesTransferByFgBg Bug: 153174569 Change-Id: Ia0eaeb68183ff5de8936011fbacab177fa3a7d9a