Fix art_quick_osr_stub signature.

This is what's causing all the LLVM miscompilations.
Asm implementation treats the argument as int64_t (by using the full
register in address arithmetic).

Bug: 112438058
Bug: 110779387
Test: boot with new toolchain
Change-Id: I23527252011c93ada2d2b8e2a2268ed456e03c3d