Switching time control modes during an execution

[p-offtermatt]

Is your feature request related to a problem? Please describe.
When running a test, it might be that for certain parts you want automatic block production and don't so much care about the exact contents of blocks, and then there is a critical part where you need to control behaviour very precisely.
For example, while IBC connections are set up, you want blocks produced automatically, and then you want full control.

Describe the solution you'd like
It could be helpful to have ways to switch "time control modes" during the execution.
The way that is likely best would be via an rpc endpoint