Move random_test_initializer to separate file [SyncWith: crypto3-zk#328] #273

All 79 tests pass in 58s

  30 files +  2   30 suites +2 58s ⏱️ +34s
  79 tests +29   79 ✔️ +30 0 💤 ±0 0 ❌ - 1
168 runs +58 168 ✔️ +60 0 💤 ±0 0 ❌ - 2

Results for commit 2c082fd. ± Comparison against earlier commit 99382c7.