Add 16 single-contract benchmarks from purplebench

[msooseth]

Summary

• Adds 16 flattened, on-chain mainnet contracts to benchmark_data/ (WETH9, UniswapV3Pool, Morpho, BoredApeYachtClub, FiatTokenV2_2, Vault, PoolManager, TetherToken, EulerSwap, OETH, EtherfiLiquidityPool, RocketDepositPool, AaveV4HubInstance, ENSRegistryWithFallback, Poap, OCRConfigurationStoreEVMSimple).
• Sources from DanielVF/purplebench at commit ad8035580b71937282d2a760c71a14b07dcfb483. Once that repo has a tag, we'll swap the SHA for the tag.
• Each contract has zero imports / zero NPM deps — they're pre-flattened on-chain verified source. Pragmas relaxed to >=0.8.24 where present so any newer solc compiles them (only Vault had an active pragma).
• Each entry records its mainnet_address and is tagged purplebench, mainnet, single-contract.

Big thanks to @DanielVF for curating and flattening these contracts in purplebench.

Test plan

• All 16 standard-jsons compile cleanly with solc 0.8.36-develop under both evmasm and ir pipelines (32 builds, 0 errors).
• solc-bench list --benchmark-dir ./benchmark_data lists all 24 entries (8 existing + 16 new).
• solc-bench run --tags purplebench --iterations 1 completes for all 16 contracts with bytecode produced.
• Reviewer: confirm the SHA-as-version convention is acceptable as a placeholder until purplebench tags a release.

🤖 Generated with Claude Code

[DanielVF]

You could probably rename Vault to SimpleVaultExample, or remove it - it was intended to be an extremely minimal test for human bytecode reading.