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

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