Mounting real directories into worker will cause init to start tracking
the mount point through dev.mnt. This causes issues, so we are forced
to recursively reconstruct the mirror directory structure from scratch.
Fix#9316
Due to various reasons, we cannot directly mount module files in /data
into the real paths. Instead we bind mount the module root directory and
remount this mirror with specific mount-point flags. Relevant to this
bug, the module mount is mounted as read-only, which means the file
attribute copy operation could fail in certain configurations.
The fix here is to always copy file attributes into writable locations,
so either in the tmpfs worker directory, or in the module directory
under /data.
A new test case is added to make sure this regression will no longer
happen again in the future.
Fix#9139
Magisk binary mounting logic is not very clear now. In this commit, it
is rewritten in a more robust way. Now it has following cases in mind:
1) Device has a su binary, magisk need to overlay it
2) Choose the PATH with least files to reduce bind mount
3) Filter path which is not suitable
