Merge branch 'bc/hash-independent-tests'

Many tests hardcode the raw object names, which would change once
we migrate away from SHA-1.  While some of them must test against
exact object names, most of them do not have to use hardcoded
constants in the test.  The latter kind of tests have been updated
to test the moral equivalent of the original without hardcoding the
actual object names.

* bc/hash-independent-tests: (28 commits)
  t5300: abstract away SHA-1-specific constants
  t4208: abstract away SHA-1-specific constants
  t4045: abstract away SHA-1-specific constants
  t4042: abstract away SHA-1-specific constants
  t4205: sort log output in a hash-independent way
  t/lib-diff-alternative: abstract away SHA-1-specific constants
  t4030: abstract away SHA-1-specific constants
  t4029: abstract away SHA-1-specific constants
  t4029: fix test indentation
  t4022: abstract away SHA-1-specific constants
  t4020: abstract away SHA-1-specific constants
  t4014: abstract away SHA-1-specific constants
  t4008: abstract away SHA-1-specific constants
  t4007: abstract away SHA-1-specific constants
  t3905: abstract away SHA-1-specific constants
  t3702: abstract away SHA-1-specific constants
  t3103: abstract away SHA-1-specific constants
  t2203: abstract away SHA-1-specific constants
  t: skip pack tests if not using SHA-1
  t4044: skip test if not using SHA-1
  ...

diff --cc t/t1400-update-ref.sh
Simple merge

diff --cc t/t1512-rev-parse-disambiguation.sh
Simple merge

diff --cc t/t2025-worktree-add.sh
Simple merge

diff --cc t/t4014-format-patch.sh
Simple merge

diff --cc t/t5300-pack-object.sh
Simple merge

diff --cc t/t5516-fetch-push.sh
Simple merge

diff --cc t/test-lib.sh
Simple merge