Add JSON.pm to third_party

third_party/JSON/JSON-2.59/t/e10_bignum.t

+
+use strict;
+use Test::More;
+BEGIN { plan tests => 6 };
+
+BEGIN { $ENV{PERL_JSON_BACKEND} = "JSON::backportPP"; }
+
+use JSON -support_by_pp;
+
+eval q| require Math::BigInt |;
+
+SKIP: {
+    skip "Can't load Math::BigInt.", 6 if ($@);
+
+    my $v = Math::BigInt->VERSION;
+    $v =~ s/_.+$// if $v;
+
+my $fix =  !$v       ? '+'
+          : $v < 1.6 ? '+'
+          : '';
+
+
+my $json = new JSON;
+
+$json->allow_nonref->allow_bignum(1);
+$json->convert_blessed->allow_blessed;
+
+my $num  = $json->decode(q|100000000000000000000000000000000000000|);
+
+isa_ok($num, 'Math::BigInt');
+is("$num", $fix . '100000000000000000000000000000000000000');
+is($json->encode($num), $fix . '100000000000000000000000000000000000000');
+
+$num  = $json->decode(q|2.0000000000000000001|);
+
+isa_ok($num, 'Math::BigFloat');
+is("$num", '2.0000000000000000001');
+is($json->encode($num), '2.0000000000000000001');
+
+
+}