According to corecheck, feature_block is the slowest functional test and it’s taking about 70 seconds to run. feature_block is a huge functional test that tests many things - large re-orgs, block with invalid transactions, disabled opcodes, sigop counts, etc. These things are not necessarily coupled and could be broken into subtests and then we could run some of them instead of the whole test (see #30991) when necessary.
The motivation for it is our mutation testing analysis. feature_block is important on the analysis of some files but not the whole test. That said, spending 70 seconds on a single test per mutant is making our analysis to take a long time.
