binary search tool: (Refactor) Extract common scripts into common folder

Refactor warning! Move install.sh, boot_test.sh, and interactive_test.sh
into common folder so they can be shared by both package and object
bisectors. To allow this sharing, sysroot_wrapper now has a setup script
similar to cros_pkg. All scripts now source common/common.sh.

TEST=Run unit tests, run system tests, run couple iterations of install
script for both bisectors.

Change-Id: I9e164b4e6b842ff321c2400201e6ac0984f99088
Reviewed-on: https://chrome-internal-review.googlesource.com/268027
Commit-Ready: Cassidy Burden <cburden@google.com>
Tested-by: Cassidy Burden <cburden@google.com>
Reviewed-by: Caroline Tice <cmtice@google.com>
29 files changed