Cranelift: add/modify mid-end opt rules

[myunbin]

Add new opt rules:

• x /u (1 << y) ==> x >>u y
• (x ^ y) ^ (x ^ z) ==> y ^ z
• (-x) & 1 ==> x & 1
• (x >>s y) >s -1 ==> x >=s 0
• (x >>s y) >=s 0 ==> x >=s 0
• (x & y) & (x | z) ==> x & y
• (x & y) | (x | z) ==> x | z
• (x & y) | (x ^ y) ==> x | y
• ~((~x) - y) ==> x + y
• rotl(x, k) == rotl(y, k) ==> x == y
• ~((~x) >>s y) ==> x >>s y

Apply all_zero helper to existing zero-constant rules in:

{arithmetic, bitops, cprop, extends, icmp, selects, shifts}.isle

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cc @avanhatt, @cfallin, @fitzgen, @mmcloughlin

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[cfallin]

LGTM, thanks!