Merge branch 'bc/hash-independent-tests-part-6'
Test updates to prepare for SHA-2 transition continues.
* bc/hash-independent-tests-part-6:
t4048: abstract away SHA-1-specific constants
t4045: make hash-size independent
t4044: update test to work with SHA-256
t4039: abstract away SHA-1-specific constants
t4038: abstract away SHA-1 specific constants
t4034: abstract away SHA-1-specific constants
t4027: make hash-size independent
t4015: abstract away SHA-1-specific constants
t4011: abstract away SHA-1-specific constants
t4010: abstract away SHA-1-specific constants
t3429: remove SHA1 annotation
t1305: avoid comparing extensions
rev-parse: add a --show-object-format option
t/oid-info: add empty tree and empty blob values
t/oid-info: allow looking up hash algorithm name