Add various utility meta-transforms to Beam. #129581

All 107 tests pass, 1 skipped in 1m 31s

15 files - 762 15 suites - 762 1m 31s ⏱️ - 28m 20s
108 tests - 6 617 107 ✅ - 6 592 1 💤 - 25 0 ❌ ±0
108 runs - 6 622 107 ✅ - 6 597 1 💤 - 25 0 ❌ ±0

Results for commit efcf1ba. ± Comparison against earlier commit 71d97b6.