Port netstack, hostinet, and netlink sockets to VFS2.

All three follow the same pattern:
1. Refactor VFS1 sockets into socketOpsCommon, so that most of the methods can
   be shared with VFS2.
2. Create a FileDescriptionImpl with the corresponding socket operations,
   rewriting the few that cannot be shared with VFS1.
3. Set up a VFS2 socket provider that creates a socket by setting up a dentry
   in the global Kernel.socketMount and connecting it with a new
   FileDescription.

This mostly completes the work for porting sockets to VFS2, and many syscall
tests can be enabled as a result.
There are several networking-related syscall tests that are still not passing:
1. net gofer tests
2. socketpair gofer tests
2. sendfile tests (splice is not implemented in VFS2 yet)

Updates #1478, #1484, #1485

PiperOrigin-RevId: 309457331

0 files changed, 0 insertions, 0 deletions