fixes issue 1027
fixes issue 1027

+ Hide the jmp from landing pad to syscall instr from the client, to
  match what DR did before syscalls used landing pads (pre-i#901).
+ Go ahead and add a mapping for that jmp, just in case.

git-svn-id: ed337ca7cdb08c0ba29d8fe58632bb7686892c2d@1790 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6

rnk/dynamorio,rnk/dynamorio,rnk/dynamorio,rnk/dynamorio,rnk/dynamorio