crypto: limit sha1 or sha512 blocks processed at once in assembly - #80916

Problem

GC stop-the-world is slow if a large input is passed to sha1/sha512

Root cause: Write passes unbounded input to block(), and assembly is not
preemptible. CL 671098 bounded md5 and sha256 for #64417; sha1 and sha512 have
the same problem and were not covered.

Stop-the-world (improved)

/sched/pauses/stopping/gc:seconds, the time the runtime spends waiting for every
P to halt, worst pause while hashing a 64 MiB buffer. linux/amd64, EPYC 4344P,
GOMAXPROCS=2

                     before        after      pauses >1ms
    crypto/sha1      25.166ms      197us         2 -> 0
    crypto/sha512    67.109ms      1.049ms       2 -> 0

BenchmarkSTW, added here, reports the same effect as the wall time of one
runtime.GC() that overlaps the hash:

```
    GOMAXPROCS=2 go test -run='^$' -bench=BenchmarkSTW -count=6 -benchtime=2s crypto/sha1 crypto/sha512
    benchstat before.txt after.txt

           │ gcwait-sec/op │ gcwait-sec/op  vs base               │
    sha1        24988.7µ ± 0%    319.3µ ± 13%  -98.72% (p=0.002 n=6)
    sha512      61965.8µ ± 0%    475.8µ ± 60%  -99.23% (p=0.002 n=6)
```

Throughput (no degradations)

```
    for i in $(seq 8); do
      GOMAXPROCS=2 go test -run='^$' -bench=BenchmarkHash -count=3 -benchtime=200ms crypto/sha1 crypto/sha512
    done
    benchstat before.txt after.txt

    sha1                     sec/op        sec/op     vs base
    Hash8Bytes/New-2     57.70n ± 6%   57.78n ± 5%  ~ (p=0.649 n=24)
    Hash8Bytes/Sum-2     52.50n ± 0%   52.46n ± 0%  ~ (p=0.770 n=24)
    Hash320Bytes/New-2   174.3n ± 0%   174.3n ± 0%  ~ (p=0.888 n=24)
    Hash320Bytes/Sum-2   171.6n ± 0%   171.7n ± 0%  ~ (p=0.368 n=24)
    Hash1K/New-2         433.8n ± 0%   433.9n ± 0%  ~ (p=0.922 n=24)
    Hash1K/Sum-2         432.1n ± 0%   432.0n ± 0%  ~ (p=0.988 n=24)
    Hash8K/New-2         3.083µ ± 0%   3.083µ ± 0%  ~ (p=0.896 n=24)
    Hash8K/Sum-2         3.083µ ± 0%   3.082µ ± 0%  ~ (p=0.938 n=24)
    Hash256K/New-2       96.96µ ± 0%   96.94µ ± 0%  ~ (p=0.657 n=24)
    Hash256K/Sum-2       96.90µ ± 0%   96.96µ ± 0%  ~ (p=0.092 n=24)
    Hash1M/New-2         387.9µ ± 0%   388.0µ ± 0%  ~ (p=0.214 n=24)
    Hash1M/Sum-2         387.8µ ± 0%   387.9µ ± 0%  ~ (p=0.428 n=24)
    geomean              2.796µ        2.796µ       +0.01%

    sha512                    sec/op        sec/op     vs base
    Hash8Bytes/New-2      149.4n ± 0%   149.3n ± 0%       ~ (p=0.849 n=24)
    Hash8Bytes/Sum384-2   157.6n ± 0%   158.0n ± 0%  +0.25% (p=0.003 n=24)
    Hash8Bytes/Sum512-2   157.5n ± 0%   157.8n ± 0%       ~ (p=0.106 n=24)
    Hash1K/New-2          1.082µ ± 0%   1.084µ ± 0%       ~ (p=0.053 n=24)
    Hash1K/Sum384-2       1.089µ ± 0%   1.089µ ± 0%       ~ (p=0.329 n=24)
    Hash1K/Sum512-2       1.093µ ± 0%   1.091µ ± 0%       ~ (p=0.538 n=24)
    Hash8K/New-2          7.655µ ± 0%   7.650µ ± 0%  -0.07% (p=0.045 n=24)
    Hash8K/Sum384-2       7.668µ ± 0%   7.652µ ± 0%  -0.21% (p=0.000 n=24)
    Hash8K/Sum512-2       7.660µ ± 0%   7.649µ ± 0%  -0.14% (p=0.000 n=24)
    Hash256K/New-2        240.5µ ± 0%   239.9µ ± 0%       ~ (p=0.173 n=24)
    Hash256K/Sum384-2     240.7µ ± 0%   240.0µ ± 0%  -0.32% (p=0.024 n=24)
    Hash256K/Sum512-2     240.2µ ± 0%   240.0µ ± 0%       ~ (p=0.136 n=24)
    Hash1M/New-2          960.8µ ± 0%   962.4µ ± 0%       ~ (p=0.519 n=24)
    Hash1M/Sum384-2       961.2µ ± 0%   961.0µ ± 0%       ~ (p=0.814 n=24)
    Hash1M/Sum512-2       960.8µ ± 0%   960.5µ ± 0%       ~ (p=0.878 n=24)
    geomean               12.44µ        12.44µ       -0.04%
```

References:
- Go stdlib sha256, md5: #64417