Add various utility meta-transforms to Beam. #129581

All 202 tests pass, 70 skipped in 2m 8s

2 files - 775 2 suites - 775 2m 8s ⏱️ - 27m 43s
272 tests - 6 453 202 ✅ - 6 497 70 💤 +44 0 ❌ ±0
278 runs - 6 452 202 ✅ - 6 502 76 💤 +50 0 ❌ ±0

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