Add `setjmp` and `longjmp` functions for tizenrt-artik05x target

[glistening]

Problem

Currently tizenrt-artik05x does not support longjmp/setjmp correctly.
I tried to use longjmp/setjmp implementation from nuttx-stm32f4 port.

But it shows following error:

System Information:
        Verarm_undefinedinsn: 
Undefined instruction at 0x4130b58
up_assert: Assertion failed at file:armv7-r/arm_undefinedinsn.c line: 107 task: appmain

Looking for Solution

Since artik05x is cortex-r4, not cortex-m4, I looked for vstm and vldm in Cortex R4 Technical Manual. And I found vldm in this manual, however, there is no vstm. So I removed vstm from nuttx-stm32f4 longjmp/setjmp and it escapes me from above error. ( vldm does not cause the undefined instruction error. ) So I will expand the vstm instruction on tizenrt-artik05x and run some tests in order to make sure it is correct.

[robertsipka]

Just a question about the setjmp/longjmp implementation that may be a different from the source of the NuttX port. Is the hard-float mode enabled? The stm32f4 NuttX port's setjmp implementation expects that the hard-float mode is used and stores s16-s31 vfp registers to buffer, pointed with r0 register, and increases the register on size of stored data. If not, I think removing the vstm instruction is ok, but also needs to remove the vldm instruction.

[glistening]

@robertsipka tizenrt-artik05x uses -mfpu=vfpv3. But I found that artik05x has no floating-point unit and got confirmed by artik05x team. Thus we can (and have to) remove vstm and vldm as you commented.

I would like to fix my wrong sentence:

vldm does not cause the undefined instruction error.

• vldm also causes undefined instruction assertion failure.
  If I move vldm in place of vstm (e.g., setjmp), the same assertion failure occurs.
  ( longjmp seems not be called in simple hello jerry example. It is the reason vldm seems ok although it isn't. )

• Summary of VFP instructions says both of vldm and vstm should work in vfpv3.

[glistening]

@robertsipka I will check the correctness on tizenrt-artik05x by running tests under tests/jerry/fail/*. Segment faults from the earlier longjmp/setjmp implementation are expected to be eliminated.