use crc32 from libdeflate, remove bundled crc32 code

[ThomasWaldmann]

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[codecov-commenter]

Codecov Report

Merging #6387 (07f4d53) into master (d9d1e44) will not change coverage.
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  Files          39       39           
  Lines       10457    10457           
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  Hits         8696     8696           
  Misses       1254     1254           
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[ThomasWaldmann]

Local test on MBA, macOS 12 (M1 cpu):

Name (time in us)                Mean             StdDev                Median                   OPS          
--------------------------------------------------------------------------------------------------------------
test_zlib_crc32              328.8660 (1.0)       9.6358 (1.0)        326.3340 (1.0)      3,040.7518 (1.0)    
test_deflate_crc32         1,261.1159 (3.83)     76.3716 (7.93)     1,236.2500 (3.79)       792.9485 (0.26)   
test_borg_crc32_slice8     4,386.7739 (13.34)    35.7977 (3.72)     4,375.3965 (13.41)      227.9580 (0.07)   
--------------------------------------------------------------------------------------------------------------

On github CI, macOS (x64):

Name (time in ms)            Mean            StdDev            Median                 OPS          
---------------------------------------------------------------------------------------------------
test_zlib_crc32            3.0155 (1.0)      0.2969 (1.02)     2.9466 (1.0)      331.6165 (1.0)    
test_deflate_crc32         3.1616 (1.05)     0.2898 (1.0)      3.0889 (1.05)     316.2978 (0.95)   
test_borg_crc32_slice8     4.5672 (1.51)     0.24.. (1.39)     4.5125 (1.53)     218.9503 (0.66)   
---------------------------------------------------------------------------------------------------

On github CI, Linux (x64):

Name (time in us)                Mean             StdDev                Median                   OPS          
--------------------------------------------------------------------------------------------------------------
test_deflate_crc32           589.7927 (1.0)       5.6325 (1.24)       588.5160 (1.0)      1,695.5110 (1.0)    
test_borg_crc32_clmul        591.3464 (1.00)      4.5526 (1.0)        589.60.. (1.00)     1,691.0562 (1.00)   
test_borg_crc32_slice8     4,550.2839 (7.72)     20.4307 (4.49)     4,555.1760 (7.74)       219.7665 (0.13)   
test_zlib_crc32            8,602.3128 (14.59)     7.8226 (1.72)     8,600.7385 (14.61)      116.2478 (0.07)   
--------------------------------------------------------------------------------------------------------------

[ThomasWaldmann]

OK, so guess this means:

if macOS:
     use zlib.crc32
else:
    use deflate.crc32

And we'll remove our bundled crc32 code, looks like the stuff in (lib)deflate is comparable or even better.