[C++] STL allocator doesn't check for multiplication overflow

[asfimport]

The MemoryPool-backed STL allocator defined in arrow/stl.h has the following code:

    Status s = pool_->Allocate(n * sizeof(T), &data);

but n * sizeof(T) might silently overflow and lead to an incorrect allocation size.

Reporter: Antoine Pitrou / @pitrou

_{Note: This issue was originally created as ARROW-15615. Please see the migration documentation for further details.}

[pitrou]

Issue resolved by pull request 51477
#51477

[pitrou]

@aikhanjum Can you post here so that we can assign this issue to you?