adb: improve socket tests.

Make it so that the socket tests don't leak until your machine blows up
by switching an infinite loop into an assertion failure.

Bug: http://b/74616284
Test: adb_test
Change-Id: If618c26b224b660548454f542cab79bebe46f80e
(cherry picked from commit ecb96ac04d7be37eae168658d50003434407b1ac)
1 file changed