Well. I don't know. Those two programs don't really do the same thing. There's an awful lot of comparisons in the second one. After making the awk program more similar to the Perl program, and using mawk instead of gawk (which is quite a bit slower) the numbers look a bit different:
$ seq 100000000 > /tmp/numbers
$ time perl -MData::Dumper -ne '$n{length($_)}++; END {print Dumper(%n)}' /tmp/numbers
$VAR1 = '7';
$VAR2 = 900000;
$VAR3 = '8';
$VAR4 = 9000000;
$VAR5 = '5';
$VAR6 = 9000;
$VAR7 = '4';
$VAR8 = 900;
$VAR9 = '6';
$VAR10 = 90000;
$VAR11 = '10';
$VAR12 = 1;
$VAR13 = '2';
$VAR14 = 9;
$VAR15 = '3';
$VAR16 = 90;
$VAR17 = '9';
$VAR18 = 90000000;
real 0m16.483s
user 0m16.071s
sys 0m0.352s
$ time mawk '{ lengths[length($0)]++ } END { max = 0; for(l in lengths) if (int(l) > max) max = int(l); print max; }' /tmp/numbers
9
real 0m5.980s
user 0m5.493s
sys 0m0.457s