fix(ssa_fuzzer): nested conditions in loops

[defkit]

Description

Problem*

Ssa fuzzer didnt support nested conditions in loops, or programs like this:

fn main(x: Field, condition: bool) -> pub Field {
  let mut y = x;
  for i in 0..4 {
    if condition {
      for _ in 0..4 {
        y *= x;
      }
    }
  }
  y
}

Summary*

Additional Context

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Test Suite Duration'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: 7079d34	Previous: 3838c69	Ratio
test_report_AztecProtocol_aztec-packages_noir-projects_noir-protocol-circuits_crates_blob	175 s	141 s	1.24

This comment was automatically generated by workflow using github-action-benchmark.

CC: @TomAFrench