Improve range checks of options for pg_test_fsync and pg_test_timing

Both tools never had safeguard checks for the options provided, and it
was possible to make pg_test_fsync run an infinite amount of time or
pass down buggy values to pg_test_timing.

These behaviors have existed for a long time, with no actual complaints,
so no backpatch is done.  Basic TAP tests are introduced for both tools.

Author: Michael Paquier
Reviewed-by: Peter Eisentraut
Discussion: https://postgr.es/m/20200806062759.GE16470@paquier.xyz

src/bin/pg_test_fsync/t/001_basic.pl

@@ -0,0 +1,25 @@
+use strict;
+use warnings;
+
+use Config;
+use TestLib;
+use Test::More tests => 12;
+
+#########################################
+# Basic checks
+
+program_help_ok('pg_test_fsync');
+program_version_ok('pg_test_fsync');
+program_options_handling_ok('pg_test_fsync');
+
+#########################################
+# Test invalid option combinations
+
+command_fails_like(
+	[ 'pg_test_fsync', '--secs-per-test', 'a' ],
+	qr/\Qpg_test_fsync: error: invalid argument for option --secs-per-test\E/,
+	'pg_test_fsync: invalid argument for option --secs-per-test');
+command_fails_like(
+	[ 'pg_test_fsync', '--secs-per-test', '0' ],
+	qr/\Qpg_test_fsync: error: --secs-per-test must be in range 1..4294967295\E/,
+	'pg_test_fsync: --secs-per-test must be in range');