finish build_target_lib.get_default_sysroot_path migration [reland]

This allows us to drop the build_target_lib import from cros_build_lib.

The failing platform2 code that caused this to revert before has been
fixed, and cs/ doesn't show any other latent hits.

BUG=chromium:1170007
TEST=CQ passes

Change-Id: I284d99fc2570eff7c4e843140efdfe5a56acc8d5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2814898
Tested-by: Mike Frysinger <vapier@chromium.org>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Sergey Frolov <sfrolov@google.com>
Reviewed-by: Sergey Frolov <sfrolov@google.com>
diff --git a/scripts/cros_fuzz.py b/scripts/cros_fuzz.py
index 4492a20..2f376a9 100644
--- a/scripts/cros_fuzz.py
+++ b/scripts/cros_fuzz.py
@@ -50,6 +50,7 @@
 from elftools.elf.elffile import ELFFile
 import lddtree
 
+from chromite.lib import build_target_lib
 from chromite.lib import commandline
 from chromite.lib import constants
 from chromite.lib import cros_build_lib
@@ -145,7 +146,7 @@
     Returns:
       The path to the sysroot (the value of path_to_sysroot).
     """
-    cls.path_to_sysroot = cros_build_lib.GetSysroot(board)
+    cls.path_to_sysroot = build_target_lib.get_default_sysroot_path(board)
     return cls.path_to_sysroot
 
   @property