Cranelift: add/modify mid-end opt rules

[myunbin]

Add new opt rules:

• (x - y) == 0 ==> x == y
• (x - y) != 0 ==> x != y
• (x ^ y) == 0 ==> x == y
• (x ^ y) != 0 ==> x != y
• (x ^ y) == x ==> y == 0
• (x + y) != x ==> y != 0
• x != -y ==> x != y
• (x == y) ? 0 : (x - y) ==> x - y
• (c ? y : z) + (c ? z : y) ==> z + y
• (x != y) ? (x - y) : 0 ==> x - y

Apply all_zero helper for existing rules:

• x & 0 == 0 & x == x & not(x) == not(x) & x == 0

[github-actions]

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

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