kleaf: Add initial test for setting up DDK workspace.

Add tests for the case where @kleaf is in a parent
directory of where ddk_workspace is. This is
unusual; this use case is reserved for testing
purposes only.

The test includes:
- building @kleaf//common:kernel_aarch64
  (init_ddk --local)
- building external drivers against the kernel
  from sources
- building in-tree dirvers against the kernel from
  sources
- building images from these drivers.

Add these tests to integration test.

Caveat:
- b/338439996: The test uses a script to fake the
  offline behavior of init_ddk that copies
  local_path_override
- b/338440785: The test relies on an empty
  WORKSPACE.bzlmod
  file which should technically be avoided, but
  needed now to work around an error in rules_cc.

Bug: 338263410
Test: TH
Change-Id: I1c30ffa64a24019cb0faf22c166bb69b4f96117e
1 file changed