fix(pprof parsing): decrease number of allocations during stack hash

[korniltsev]

There was an attempt to do the whole hashing on the stack

	var hashes [64 + 32]uint64
	s := hashes[:]

unfortunately it should have been

	s := hashes[:0]

also

with this code

	sh.Data = uintptr(unsafe.Pointer(&s[0]))

hashes escapes to heap
and with this does not escape

ps := uintptr(unsafe.Pointer(&s[0]))
sh.Data = ps

which is weird

I rewrote to just hash on a single preallocated heap/arena slice

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
webapp/public/assets/app.js	1006.8 KB (0%)	20.2 s (0%)	3.7 s (-4.34% 🔽)	23.9 s
webapp/public/assets/app.css	19.88 KB (0%)	398 ms (0%)	0 ms (+100% 🔺)	398 ms
webapp/public/assets/styles.css	9.6 KB (0%)	192 ms (0%)	0 ms (+100% 🔺)	192 ms
packages/pyroscope-flamegraph/dist/index.js	632.75 KB (0%)	12.7 s (0%)	1.7 s (-13.31% 🔽)	14.3 s
packages/pyroscope-flamegraph/dist/index.node.js	633.45 KB (0%)	12.7 s (0%)	749 ms (-12.32% 🔽)	13.5 s
packages/pyroscope-flamegraph/dist/index.css	8.11 KB (0%)	163 ms (0%)	0 ms (+100% 🔺)	163 ms

[codecov]

Codecov Report

Base: 66.98% // Head: 66.98% // No change to project coverage 👍

Coverage data is based on head (0d9d43d) compared to base (32593be).
Patch has no changes to coverable lines.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1822   +/-   ##
=======================================
  Coverage   66.98%   66.98%           
=======================================
  Files         173      173           
  Lines        5875     5875           
  Branches     1575     1575           
=======================================
  Hits         3935     3935           
  Misses       1929     1929           
  Partials       11       11           

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