Bring back printing reason with `-print-allocs`

[applejag]

The -print-allocs flag is super useful when finding out allocations, especially when it printed the reason, to understand why something got pushed to the heap

But in #5220 you removed the printing of the reason why something is moved to the heap.

That PR brought in the very nice feature of showing the output using the Go coverage tool. Very cool!

But I'd still want to see the reason behind each heap allocation.

Could you bring back printing of the reason? Maybe as a separate flag?

[digitalentity]

I suggest reverting the #5220 to restore the old behavior of -print-allocs. If we actually need to feed the output to go coverage tool we should have a separate flag like -print-allocs-cov or something like that.