ci: stop building for Android in a container

[finagolfin]

This will fix the recent break because I updated the official SDK workflow script, as we only run that one on the GitHub runner directly, and stop downloading the NDK on every run.

I've also greatly broadened out the testing matrix, as all these other options should work too. We can trim them back down, if wanted, after trying a run.

[finagolfin]

@madsodgaard, the latest Feb. 24 trunk snapshot SDK is failing, seemingly in the Java build step, whereas the new 6.3 snapshot builds I'm adding in this pull all passed. Any idea what's going on?

[finagolfin]

Maybe this line?

Error executing swiftc -print-target-info

I see it in multiple jobs with trunk, but not 6.3. 🤨

[ktoso]

I'll see what I can find out here but cannot today sadly. Thank you for the PR!

[finagolfin]

OK, rolling back to the container got the Android build working again, so I think I know what the problem is. Using a container like this works but is wasteful, as you're installing a container with the latest trunk snapshot toolchain pre-installed, then downloading the NDK and latest trunk snapshot toolchain again on every CI run. I think the reason that works though is that the pre-installed toolchain is added to the PATH, whereas the one downloaded by the upstream script is not, but invoking swiftc directly from the PATH is apparently required by your plugin.

I'll try modifying the upstream script after downloading it in the CI here, so that it also adds the toolchain it downloads to the PATH: that should finally fix running in the GitHub runner with no container.