lib: chroot_lib: Add {sudo_,}run() wrapper

It's easy for cros_build_lib.run(enter_chroot=True) callers to get
chroot parameters wrong. Supply a helper, which makes doing the Right
Thing a lot shorter to type.

So far, I'm only converting callers that already supplied chroot_args.

BUG=none
TEST=./run_tests

Change-Id: Ice0f82eea1744d6f9a53e7b5a9e89031ae50423a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4704418
Reviewed-by: Alex Klein <saklein@chromium.org>
Commit-Queue: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
diff --git a/api/router.py b/api/router.py
index ea59e8c..50fe6fe 100644
--- a/api/router.py
+++ b/api/router.py
@@ -543,13 +543,10 @@
             ]
 
             try:
-                result = cros_build_lib.run(
+                result = chroot.run(
                     cmd,
-                    enter_chroot=True,
                     cwd=constants.SOURCE_ROOT,
-                    chroot_args=chroot.get_enter_args(),
                     check=False,
-                    extra_env=chroot.env,
                 )
             except cros_build_lib.RunCommandError:
                 # A non-zero return code will not result in an error, but one