AArch64: Add transition assembly to wrapper native functions.

There is slight difference between managed code ABI and AAPCS. We
can make managed code ABI to be the same with AAPCS. But considering
that, we might introduce more differences later for performance. It
is better to have a wrapper to deal with the differences.

Change-Id: I46ced072e9e3a83f713d2bf86fa478fc6144ee81
3 files changed