Simplify DDK and refactor VMO slice

[wangrunji0408]

• Clean some dead code.
• Simplify DDK.
  • Make PinnedMemoryToken a RAII object (unpin on drop).
• Refactor VMO slice.
  • Separate it from VMObjectPaged module to a new struct VMObjectSlice.
• Implement 2 syscalls for libos.
  • sys_futex_wake_handle_close_thread_exit
  • sys_clock_read

[github-actions]

Pull Request Test Coverage Report for Build 101086097

• 6 of 147 (4.08%) changed or added relevant lines in 12 files are covered.
• 11 unchanged lines in 7 files lost coverage.
• Overall coverage increased (+0.2%) to 25.887%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
zircon-syscall/src/vmo.rs	0	1	0.0%
zircon-object/src/dev/iommu.rs	0	3	0.0%
zircon-syscall/src/object.rs	0	3	0.0%
zircon-object/src/dev/pmt.rs	0	5	0.0%
zircon-syscall/src/time.rs	0	6	0.0%
zircon-object/src/vm/vmo/mod.rs	1	10	10.0%
zircon-object/src/vm/vmo/paged.rs	3	15	20.0%
zircon-object/src/dev/bti.rs	0	14	0.0%
zircon-syscall/src/ddk.rs	0	17	0.0%
zircon-object/src/vm/vmo/slice.rs	0	71	0.0%

Files with Coverage Reduction	New Missed Lines	%
zircon-object/src/vm/vmo/mod.rs	1	35.19%
zircon-object/src/vm/vmo/paged.rs	1	47.18%
zircon-object/src/vm/vmo/physical.rs	1	24.14%
zircon-syscall/src/object.rs	1	0%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/numeric-enum-macro-0.2.0/src/lib.rs	2	0%
zircon-syscall/src/ddk.rs	2	0%
zircon-object/src/dev/bti.rs	3	0%

Totals
Change from base Build 100372911:	0.2%
Covered Lines:	1518
Relevant Lines:	5864

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 101086097

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 6 of 147 (4.08%) changed or added relevant lines in 12 files are covered.
• 11 unchanged lines in 7 files lost coverage.
• Overall coverage increased (+0.2%) to 25.887%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
zircon-syscall/src/vmo.rs	0	1	0.0%
zircon-object/src/dev/iommu.rs	0	3	0.0%
zircon-syscall/src/object.rs	0	3	0.0%
zircon-object/src/dev/pmt.rs	0	5	0.0%
zircon-syscall/src/time.rs	0	6	0.0%
zircon-object/src/vm/vmo/mod.rs	1	10	10.0%
zircon-object/src/vm/vmo/paged.rs	3	15	20.0%
zircon-object/src/dev/bti.rs	0	14	0.0%
zircon-syscall/src/ddk.rs	0	17	0.0%
zircon-object/src/vm/vmo/slice.rs	0	71	0.0%

Files with Coverage Reduction	New Missed Lines	%
zircon-object/src/vm/vmo/mod.rs	1	35.19%
zircon-object/src/vm/vmo/paged.rs	1	47.18%
zircon-object/src/vm/vmo/physical.rs	1	24.14%
zircon-syscall/src/object.rs	1	0.0%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/numeric-enum-macro-0.2.0/src/lib.rs	2	0.0%
zircon-syscall/src/ddk.rs	2	0.0%
zircon-object/src/dev/bti.rs	3	0.0%

Totals
Change from base Build 100372911:	0.2%
Covered Lines:	1518
Relevant Lines:	5864

---

💛 - Coveralls