arm64: lift sxtl, sxtl2, sshll, sshll2

[yrp604]

Partially fixes #5417

Also superficial re-ordering of the tests to make it easier to add new tests.

With both PRs targeting #5417 we get this LLIL:

  41 @ 100003ea0  s1 = [x29 - 8 {var_18}].d
  42 @ 100003ea4  s0 = s1
  43 @ 100003ea8  v0.d[0] = sx.q(v0.s[0] u>> 0 << 0)
  44 @ 100003ea8  v0.d[1] = sx.q(v0.s[1] u>> 0 << 0)
  45 @ 100003eac  d1 = int.q(d0)
  46 @ 100003eb0  d0 = 10.0
  47 @ 100003eb4  d0 = d0 f+ d1
  48 @ 100003eb8  s0 = fconvert.s(d0)
  49 @ 100003ebc  x8 = sx.q([x29 - 8 {var_18}].d)
  50 @ 100003ec0  x9 = 0x2c
  51 @ 100003ec4  x9 = x8 * x9
  52 @ 100003ec8  x8 = &main::x
  53 @ 100003ecc  x8 = x8
  54 @ 100003ed0  x8 = x8 + x9
  55 @ 100003ed4  [x8 + 0x28].d = s0
  56 @ 100003ed8  [x29 - 0xc {var_1c_1}].d = 0
  57 @ 100003edc  goto 58 @ 0x100003ee0

and this HLIL:

  10 @ 100003ea0  int64_t v1
  11 @ 100003ea0  v1.d = var_18
  12 @ 100003ea4  v0.d = v1.d
  13 @ 100003eb8  v0.d = fconvert.s(10.0 f+ int.q((v0.d u>> 0 << 0):4.d u>> 0 << 0))
  14 @ 100003ed4  *(sx.q(var_18) * 0x2c + 0x100008028) = v0.d
  15 @ 100003ed8  int32_t var_1c_1 = 0

Finally, it looks like there are some other unlifted SHL variants that would probably follow the same template. Let me know if you've come across any of these and I can take a look.

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[galenbwill]

Closing PR because superseded by e3b91f9e65646a6b9cc69d2a353ad268ee20767b