Add a simple tool to process the files produced from RAKUDO_SUBLOG.

For the moment it simply returns a count of the number of times each
subroutine is entered.

tools/sublog-report.pl

@@ -0,0 +1,20 @@
+#! perl
+
+use warnings;
+use strict;
+
+
+my %called;
+
+while (<>) {
+    chomp;
+    my ($called, $caller) = split("\t", $_, 2);
+    $called{$called}++;
+}
+
+
+my @called_keys = sort { $called{$b} <=> $called{$a} } keys %called;
+
+foreach my $key (@called_keys) {
+    printf "%9d  %s\n", $called{$key}, $key;
+}