Extremely long running time when emitting `irOptimized` for AAVE

## Description

The `irOptimized` emission takes around 40 minutes. Is slightly less if I do not request `irOptimized` but instead compile directly to EVM with `viaIR`.

The RAM usage is also over the top and close to 25 GB during the last minutes before returning the output.

## Environment

- Compiler version: 0.8.25
- Target EVM version (as per compiler settings): default
- Framework/IDE (e.g. Truffle or Remix): CLI
- Operating system: MacOS 14 Sonoma

## Steps to Reproduce

Can be reproduced with the standard JSON containing the AAVE v3 project.
Unfortunately, I could not minimize it as it seems to have flaking non-linear effects.

Command line:
`./solc-0.8.25 --standard-json json_input_compat_ir.json`

Standard JSON input:
[json_input_compat_ir.json](https://github.com/ethereum/solidity/files/15420714/json_input_compat_ir.json)

Start by running the attached json_input_compat_ir.json with ./solc-0.8.25 --standard-json and compare irOptimized emission with direct viaIR compilation. Investigate the compiler path responsible for the reported runtime and memory growth; done means identifying and addressing the cause with reproducible performance and memory measurements.

Written by the indexing model from the issue text.