Revert "Revert "Improve immune spaces logic""

Test was flaky due to missing guard page at the end of the region.

Bug: 27136196

This reverts commit 07dbbca0b42cb8da1811de8209b4a7d4becfc7b2.

Change-Id: I4eb345f34e66b8684cd71a7897e3a8caa2f84140
2 files changed