Looking at reducing CTW costs in our infra, there are a few simple improvements we can take.

CTW runners compiling 3rd party JARs normally catch lots of stray exceptions when trying to load non-existing classes, e.g. for resolving the static final fields, or preloading the constant pool. Generating stack traces for these take considerable time, and stack traces for those exceptions are not essential to debug CTW runs. So, we can summarily disable them.