Revert 226762 "Android perf tests: kill adbd on the device after..."

Revert 226762 "Android perf tests: kill adbd on the device after..."

This seems to make matters worse on sharded bots.  Possibly because
killing adbd on one device affects the host's adb connection with other devices.

> Android perf tests: kill adbd on the device after running a test.
> 
> There's some data indicating that adbd on the device sometimes
> spontaneously restores its connection.
> After running a test, let's kill adbd and wait for bit.
> 
> This is a speculative change to try to make the bots healthier.
> 
> BUG=
> 
> Review URL: https://codereview.chromium.org/25574002

TBR=bulach@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=226980

[rmcilroy, 2013-10-04 09:51:34]

Committed patchset #1 manually as r226980.