Merge branch 'bc/hash-independent-tests-part-5' into next

Preparation for SHA-256 upgrade continues in the test department.

* bc/hash-independent-tests-part-5:
  t4009: make hash size independent
  t4002: make hash independent
  t4000: make hash size independent
  t3903: abstract away SHA-1-specific constants
  t3800: make hash-size independent
  t3600: make hash size independent
  t3506: make hash independent
  t3430: avoid hard-coded object IDs
  t3404: abstract away SHA-1-specific constants
  t3306: abstract away SHA-1-specific constants
  t3305: make hash size independent
  t3301: abstract away SHA-1-specific constants
  t3206: abstract away hash size constants
  t3201: abstract away SHA-1-specific constants

diff --cc t/t3404-rebase-interactive.sh
Simple merge

diff --cc t/t3430-rebase-merges.sh
Simple merge