fix(experimental): Fix execution of match expressions with multiple branches

[jfecher]

Description

Problem*

Resolves #7323

Summary*

Our SSA flattening pass still doesn't support > 2 predecessors on a block so lower a match by jumping to a new block each time instead. Each end block is merged LIFO like nested if statements. This is less efficient than jumping to the end directly or merging the blocks tournament-bracket style but flattening supports neither of those options.

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 'Compilation Time'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: 32934cb	Previous: 899e8c8	Ratio
rollup-block-root-single-tx	123 s	101 s	1.22

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

CC: @TomAFrench