[test suite] Add support for Test::Valgrind against the perl FKO module

When --enable-valgrind is used, this commit adds support for running the
perl FKO built-in tests (in the t/ directory) under the CPAN
Test::Valgrind module.  A check is performed to see whether
Test::Valgrind is install before attempting to use it.  Any 'fko_'
function that shows up under the test output is flagged and causes the
test-suite test to fail.
[test suite, FKO module] new(), spa_data_final(), and other fcns don't require key length args
[test suite] minor Test::Valgrind name typo fix
Revert "[test suite] minor Test::Valgrind name typo fix"

This reverts commit 642024041534d79c897a21b2e19ef3e1ed7b2a61.
[test suite] minor Test::Valgrind name typo fix
[test suite] minor python update to use a main() function
[perl FKO] interim commit to update the perldoc info
added Test::Valgrind note to the ChangeLog
[test suite] minor wording update for Test::Valgrind test