Integration tests for 16kb dev option

Adding tests to verify end to end functionality for dev options.
This test verifies
- /data reformatting to ext4
- switching to 16kb kernel
- switching back to 4kb kernel
- Persistent notifications in page-agnostic mode
- Disabling developer option in page-agnostic mode

Test: m Enable16KbTest && atest -c Enable16KbTest
Bug: 341995374
Change-Id: Ieaa149831b5205a15b259982f0349dc94d4fae92