ARM: Use stm/ldm for live registers save/restore in SlowPathCode.

In case when there is more than 4 register to save/restore in the
SlowPathCode stm/ldm can save some code size.

Test: m test-art-target; m test-art-host

Change-Id: I2d5b44bab58b67207105302cd7d8ee3300b9040a
5 files changed