[llvm][AArch64] Copy all operands when expanding BLR_BTI bundle (#78267)

Fixes #77915

Previously I based the operand copying on expandCALL_RVMARKER but did
not understand it properly at the time. This lead to me dropping the
arguments of the function being branched to.

This fixes that by copying all operands from the BLR_BTI to the BL/BLR
without skipping anything.

I've updated the existing test by adding function arguments.