Retry on python interpreter launch failures (#2278)
Sometimes, the first time we read from the stdout of the bytecode
compiler python subprocess, we get an empty string back (no newline). If
we try to write to stdin, it will often be a broken pipe (#2245). After
we got an empty string the first time, we will get the same empty string
if we read a line again.
The details of this behavior are mysterious to me, but it seems that it
can be identified by the first empty string. We check by inserting
starting with a `Ready` message on the Python side. When we encounter
the broken state, we discard the interpreter and try again.
We have to introduce a third timeout check for the interpreter launch
itself.
Minimized test script:
```bash
#!/usr/bin/env bash
set -euo pipefail
while true; do
date --iso-8601=seconds # Progress indicator
rm -rf testenv
target/profiling/uv venv testenv -q --python 3.12
VIRTUAL_ENV=$PWD/testenv target/profiling/uv pip install -q --compile wheel==0.42.0
done
```
Run as
```
cargo build --profile profiling && bash compile_bug.sh
```
Fixes #2245
pip_compileall.py