The listen backlog seems to be more meaningful on Darwin than on Linux,
resulting in connections failing with ECONNRESET. Bump it up to the
maximum supported value to make this less likely. 128 pending
connections ought to be enough for anybody.
Bug: http://b/74616284
Test: python test_device.py
Change-Id: I5fe0205924188cf18ca1fc1204f923ab5523eeb2
Misconfigured systems can have localhost pointing to an address that
isn't 127.0.0.1 or ::1.
adb is the only caller of the libcutils socket_loopback functions, so
move them into adb and switch the implementations over to using
INADDR_LOOPBACK and in6addr_loopback, instead of resolving 'localhost'
when connecting.
Bug: http://b/37282612
Test: `killall adb; adb shell`
Test: `killall adb; ip addr del 127.0.0.1/8 dev lo; adb shell`
Change-Id: I01c1885f1d9757ad0f7b353dd04b4d1f057741c8