Minimization improvement: try to remove two operations and move operations to init and post parts

[ndkoval]

For example, for ConcurrentLinkedDequeTest, it would be better to see

| -------------------------------------- |
|     Thread 1     |      Thread 2       |
| -------------------------------------- |
| addLast(1): void |                     |
| -------------------------------------- |
| pollFirst(): 1   | addFirst(0): void   |
|                  | peekLast(): 1 [0,1] |
| -------------------------------------- |

instead of

| -------------------------------------- |
|     Thread 1     |      Thread 2       |
| -------------------------------------- |
| addLast(1): void | addFirst(0): void   |
| pollFirst(): 1   | peekLast(): 1 [0,1] |
| -------------------------------------- |

Notably, it is possible to allow the parallel part to be empty, but that would require many changes -- Lincheck currently relies on the parallel part to be non-empty.