flow-control: Add cache node optimization.

[liorgold2]

Stack:

• flow-control: Support lowering of Deconstruct node. #8116
• flow-control: Add cache node optimization. #8115 ⬅

⚠️ Part of a stack created by spr. Do not merge manually using the UI - doing so may have unexpected results.

[reviewable-StarkWare]

This change is 

[orizi]

Reviewed 4 of 4 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @liorgold2)

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crates/cairo-lang-lowering/src/lower/flow_control/create_graph/cache.rs line 12 at r1 (raw file):

/// identically.
pub struct Cache<Input> {
    cache: RefCell<UnorderedHashMap<Input, NodeId>>,

doc why refcell.