FWIW, I can't replicate your problem, but my platform uses fork emulation , and when I run your program no reaping occurs 
$ perl -d:Modlist -le " use JSON; use Time::HiRes; use Scalar::Util; u
+se POSIX; print $^V; print $^O; "
v5.12.2
MSWin32
AutoLoader             5.71
Carp                   1.17
Config
Config_git.pl
Config_heavy.pl
DynaLoader             1.10
Exporter             5.64_01
Exporter::Heavy      5.64_01
Fcntl                  1.06
JSON                   2.53
JSON::XS                2.3
List::Util             1.23
POSIX                  1.19
Scalar::Util           1.23
Tie::Hash              1.03
Time::HiRes          1.9724
XSLoader               0.15
attributes             0.12
base                   2.15
common::sense           3.4
constant               1.21
overload               1.10
vars                   1.01
warnings               1.09
warnings::register     1.01

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In reply to Re: Modification of read-only value by Anonymous Monk
in thread Modification of read-only value by Tanktalus

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