[syserror] Refactor linuxerr and error package.

Move Error struct to pkg/errors package for use in multiple places.
Move linuxerr static definitions under pkg/errors/linuxerr.
Add a lookup list for quick lookup of *errors.Error by errno. This is useful
when converting syserror errors and unix.Errno/syscall.Errrno values to
*errors.Error.
Update benchmarks routines to include conversions.

The below benchmarks show *errors.Error usage to be comparable to using
unix.Errno.

BenchmarkAssignUnix
BenchmarkAssignUnix-32                 	787875022	         1.284 ns/op
BenchmarkAssignLinuxerr
BenchmarkAssignLinuxerr-32             	1000000000	         1.209 ns/op
BenchmarkAssignSyserror
BenchmarkAssignSyserror-32             	759269229	         1.429 ns/op
BenchmarkCompareUnix
BenchmarkCompareUnix-32                	1000000000	         1.310 ns/op
BenchmarkCompareLinuxerr
BenchmarkCompareLinuxerr-32            	1000000000	         1.241 ns/op
BenchmarkCompareSyserror
BenchmarkCompareSyserror-32            	147196165	         8.248 ns/op
BenchmarkSwitchUnix
BenchmarkSwitchUnix-32                 	373233556	         3.664 ns/op
BenchmarkSwitchLinuxerr
BenchmarkSwitchLinuxerr-32             	476323929	         3.294 ns/op
BenchmarkSwitchSyserror
BenchmarkSwitchSyserror-32             	39293408	        29.62 ns/op
BenchmarkReturnUnix
BenchmarkReturnUnix-32                 	1000000000	         0.5042 ns/op
BenchmarkReturnLinuxerr
BenchmarkReturnLinuxerr-32             	1000000000	         0.8152 ns/op
BenchmarkConvertUnixLinuxerr
BenchmarkConvertUnixLinuxerr-32        	739948875	         1.547 ns/op
BenchmarkConvertUnixLinuxerrZero
BenchmarkConvertUnixLinuxerrZero-32    	977733974	         1.489 ns/op

PiperOrigin-RevId: 379806801

0 files changed, 0 insertions, 0 deletions