Merge branch 'bc/hash-independent-tests-part-7'

Preparation of test scripts for the day when the object names will
use SHA-256 continues.

* bc/hash-independent-tests-part-7:
  t5604: make hash independent
  t5601: switch into repository to hash object
  t5562: use $ZERO_OID
  t5540: make hash size independent
  t5537: make hash size independent
  t5530: compute results based on object length
  t5512: abstract away SHA-1-specific constants
  t5510: make hash size independent
  t5504: make hash algorithm independent
  t5324: make hash size independent
  t5319: make test work with SHA-256
  t5319: change invalid offset for SHA-256 compatibility
  t5318: update for SHA-256
  t4300: abstract away SHA-1-specific constants
  t4204: make hash size independent
  t4202: abstract away SHA-1-specific constants
  t4200: make hash size independent
  t4134: compute appropriate length constant
  t4066: compute index line in diffs
  t4054: make hash-size independent

diff --cc t/t5318-commit-graph.sh
Simple merge

diff --cc t/t5510-fetch.sh
Simple merge