Add a test of EC dropping X86 power into G3 after S5

This test checks if EC correctly drop X86 into G3 after S5 for 10
seconds.

BUG=chrome-os-partner:10256
TEST=Test passed.

Change-Id: I1b0669219af1420c4fe7a6b4174f9337122d8740
Reviewed-on: https://gerrit.chromium.org/gerrit/25388
Reviewed-by: Tom Wai-Hong Tam <waihong@chromium.org>
Tested-by: Vic Yang <victoryang@chromium.org>
Commit-Ready: Vic Yang <victoryang@chromium.org>
2 files changed