Fix sed command line in "Diagnostics - Flame Graphs" guide

[kazarmy]

This pr fixes the sed command line used for perf file cleanup by enabling Extended Regular Expressions (ERE) syntax, so that the first sed script (that deletes lines containing " __libc_start", "LazyCompile" etc.) works. The alternative to enabling ERE syntax is to escape (, |, ) and ? which is less elegant.

[nschonni]

Ping @nodejs/diagnostics

[kazarmy]

Hi, it's been more than a week. You can verify this fix yourself using diff -u on before/after perf files to see whether lines containing __libc_start| LazyCompile | v8::internal::| Builtin:| Stub:| LoadIC:|\[unknown\]| LoadPolymorphicIC: are actually deleted.

[ovflowd]

I can confirm that this works as intended. @kazarmy sorry for the extremely slow reply, feel free to rebase this PR and I would more than happy approve and merge it :)

But yet, @nodejs/diagnostics if y'all want to have a word here

[kazarmy]

@kazarmy sorry for the extremely slow reply

No problem ... better late than never :)

feel free to rebase this PR

Ok done

[tony-go]

I didn't have time to test it at the moment. I'll try to do it this week.