ARM64: Fix and improve MacroAssembler::Printf.

  - W-sized values passed to Printf are now handled correctly by the
    simulator. In AAPCS64, int32_t and int64_t are passed in the same
    way, so this didn't affect non-simulator builds.
  - Since Printf now records the type and size of each argument, it is
    possible to mix argument types.
  - It is now possible to print the stack pointer. There is only one
    remaining restriction: The `csp` register cannot be printed unless
    it is the current stack pointer. This is because it is modified by
    BumpSystemStackPointer when the caller-saved registers are
    preserved.

BUG=
R=rmcilroy@chromium.org

Review URL: https://codereview.chromium.org/268353005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21272 ce2b1a6d-e550-0410-aec6-3dcde31c8c00