[NTOS]: Add assertions to the paged pool and demand zero page faults, to catch possib...

[NTOS]: Add assertions to the paged pool and demand zero page faults, to catch possible errors and corruptions. These paths are not yet taken in today's builds, so they do not affect any runtime code.
[NTOS]: Add assertions regarding the portability of certain code, which will need changes on ARM/x64. These should probably be C_ASSERT's but I don't want to break Timo's build.
[NTOS]: Define MM_NOIRQL (found in assertions) instead of magical -1.
[NTOS]: Add MI_IS_SESSION_PTE macro.
[NTOS]: Export the MiXxxPte variables.
[NTOS]: Fix some typos in comments.

svn path=/trunk/; revision=47183