Changes to chroot_lib to make use of path_util with a custom chroot path

chroot_lib: chroot_path and full_path now use the path_util resolver class.
Patch includes updates to all unit tests affected by the new
inside/outside chroot behavior of chroot_lib.

BUG=b:187789472
TEST=ran _all_ unit tests under chromite.

Change-Id: I036744b33cb16844b2bcccd1c38749d00ea2b8ff
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3456625
Reviewed-by: Alex Klein <saklein@chromium.org>
Tested-by: Gilberto Contreras <gcontreras@google.com>
Commit-Queue: Gilberto Contreras <gcontreras@google.com>
diff --git a/api/controller/artifacts_unittest.py b/api/controller/artifacts_unittest.py
index 0ba737d..6d425a5 100644
--- a/api/controller/artifacts_unittest.py
+++ b/api/controller/artifacts_unittest.py
@@ -66,6 +66,7 @@
   """Basic setup for all artifacts unittests."""
 
   def setUp(self):
+    self.PatchObject(cros_build_lib, 'IsInsideChroot', return_value=False)
     self.output_dir = os.path.join(self.tempdir, 'artifacts')
     osutils.SafeMakedirs(self.output_dir)
     self.sysroot_path = '/build/target'
@@ -969,6 +970,7 @@
   chroot_name = 'chroot'
 
   def setUp(self):
+    self.PatchObject(cros_build_lib, 'IsInsideChroot', return_value=False)
     self.chroot_path = os.path.join(self.tempdir, 'chroot')
     pathlib.Path(self.chroot_path).touch()
     self.expected_filepaths = [os.path.join(self.chroot_path, fp) for fp in (