feat[next]: Extend and refactor constant folding

[SF-N]

The following new transformations are introduced:

• CANONICALIZE_OP_FUNCALL_SYMREF_LITERAL:
  literal, symref -> symref, literal, prerequisite for FOLD_FUNCALL_LITERAL, FOLD_NEUTRAL_OP
  literal, funcall -> funcall, literal, prerequisite for FOLD_FUNCALL_LITERAL, FOLD_NEUTRAL_OP
  funcall, op -> op, funcall for s[0] + (s[0] + 1), prerequisite for FOLD_MIN_MAX_PLUS
• CANONICALIZE_MINUS: a - b -> a + (-b), prerequisite for FOLD_MIN_MAX_PLUS
• CANONICALIZE_MIN_MAX: maximum(a, maximum(...)) -> maximum(maximum(...), a), prerequisite for
• FOLD_FUNCALL_LITERAL: (a + 1) + 1 -> a + (1 + 1)
• FOLD_MIN_MAX:
  maximum(maximum(a, 1), a) -> maximum(a, 1)
maximum(maximum(a, 1), 1) -> maximum(a, 1)
• FOLD_MIN_MAX_PLUS: maximum(plus(a, 1), a) -> plus(a, 1)
maximum(plus(a, 1), plus(a, -1)) -> plus(a, maximum(1, -1))
• FOLD_NEUTRAL_OP: a + 0 -> a, a * 1 -> a

In the end, unary minuses are transformed back to minus-calls where possible by UndoCanonicalizeMinus:
a + (-b) -> a - b , -a + b -> b - a, -a + (-b) -> -a - b

In addition the pass now transforms until a fixed point is reached (like in the CollapseTuple pass) instead of just transforming once. The FixedPointTransformation class from PR 1826 is used here.

Previously, large nested maximum expressions like maximum(maximum(maximum(maximum(sym, 1),...), 1), maximum(maximum(sym, 1), 1)) caused timeouts in PMAP-GO as the runtime of the domain inference increased significantly due to the large domain expressions that could not be simplified.

This replaces this PR.