Test Ubuntu 24.04 in CI workflows.

[bdice]

This PR tests Ubuntu 24.04 in CI workflows. See rapidsai/shared-workflows#248.

Contributes to rapidsai/build-planning#74.

[bdice]

It appears there is a failure due to the change to rockylinux8 for conda C++ builds (we want to build on a system with the oldest supported glibc).

Formatting build metrics
awk: cmd. line:1: error: division by zero attempted

I'll look into this (a bit later). This also affects RAFT.

[bdice]

Testing is complete. rapidsai/shared-workflows#248 has been merged, so we can close this.

[bdice]

Following up: I forgot that the fix in build.sh needed to be merged for CI to pass. That was corrected in rapidsai/raft#2474 and #420.

The decision to use python here is pragmatic: there wasn't a good alternative that I could see.

The root cause of the problem was that awk throws an error for expressions with divide-by-zero even if that branch isn't taken!

$ echo - | awk "{ if (1 > 0) { print \"yes\" } else { printf \"%.2f\", 0 / 0 } }"
awk: cmd. line:1: error: division by zero attempted

We are using shell variables to provide the $COMPILE_REQUESTS and $CACHE_HITS so the awk command sees a literal 0 / 0 and fails, even though the conditional never goes down that path. It's like a compile-time error.

Other tools like bc also fail here, due to lacking a concept of NaN. Using python is the next best choice to avoid overcomplication, and it can be done in a one-line command like the previous awk command.

HIT_RATE=$(python3 -c "print(f'{${CACHE_HITS} / ${COMPILE_REQUESTS}:.2f}' if ${COMPILE_REQUESTS} else 'nan')")