Remove explicit watchdog cancellations at end of program

The previous commit made these unnecessary.  This commit removes them.
I also removed a couple that occurred just before done_testing() and
plan() that occur at the end of the program.

Author: khwilliamson

t/io/closepid.t

@@ -42,5 +42,3 @@ SKIP:
     kill $killsig, $pid;
     open STDIN, "<&", $savein;
 }
-
-watchdog(0);

t/io/openpid.t

@@ -101,5 +101,3 @@ next_test();
 print "# waiting for process $pid4 to exit\n";
 $reap_pid = waitpid $pid4, 0;
 is( $reap_pid, $pid4, 'fourth process reaped' );
-
-watchdog(0);

t/op/sigdispatch.t

@@ -167,5 +167,3 @@ like $@, qr/No such hook: __DIE__\\0whoops at/;
     is($int_called, 1);
     is($@, "died");
 }
-
-watchdog(0);

t/op/signame_canonical.t

@@ -72,6 +72,3 @@ foreach my $dupe (@duplicate_signals) {
     is( $SIG{$dupe},           undef, "The signal $dupe is cleared after local goes out of scope." );
     is( $SIG{$canonical_name}, undef, "The signal $canonical_name is cleared after local goes out of scope." );
 }
-
-watchdog(0);
-

t/op/study.t

@@ -158,5 +158,3 @@ TODO: {
     push @got, $_ foreach $a =~ /[^x]d(?{$a .= ''})[^x]d/g;
     is("@got", 'ydyd ydyd', '#92696 $a .= \'\' inside (?{}), $a studied');
 }
-
-watchdog(0);

t/op/time.t

@@ -248,5 +248,3 @@ SKIP: {
     is scalar gmtime("NaN"), undef, '[perl #123495] gmtime(NaN)';
     is scalar localtime("NaN"), undef, 'localtime(NaN)';
 }
-
-watchdog(0);

t/op/time_loop.t

@@ -14,5 +14,3 @@ watchdog(2);
 local $SIG{__WARN__} = sub {};
 is gmtime(2**69),    undef;
 is localtime(2**69), undef;
-
-watchdog(0);

t/op/waitpid.t

@@ -35,6 +35,5 @@ watchdog(10);
 
     pass("didn't block on waitpid(0, ...)");
 }
-watchdog(0);
 
 done_testing();

t/perf/speed.t

@@ -42,6 +42,4 @@ SKIP: {
     pass("COW 1Mb strings");
 }
 
-watchdog(0);
-
 1;

t/perf/taint.t

@@ -61,6 +61,4 @@ my $taint = substr($ENV{PATH}, 0, 0); # and empty tainted string
     pass("RT #130584 pos on tainted utf8 string");
 }
 
-watchdog(0);
-
 1;