Previously, our runner image only included the most recent release of CodeQL. In order to improve stability of rollout of new CodeQL versions, we are now downloading the most recent two releases.
The change updates the Linux and Windows script variable names to match that of the Mac script, because they are mostly functionally identical. It also adds the same log messages to all scripts and ensures Mac and Windows test parity. It tests that there are two bundles in each of the OS's as well.
This will approximately double the total size and installation time of the existing CodeQL tool.
