Replace use of assertType with assertInternalType and assertInstanceOf

Replace use of assertType with assertInternalType and assertInstanceOf

These are available in phpunit since 3.5.0, which I think
is reasonable to expect people to have at this point,
especially when we actually require 3.7.0 or higher in phpunit.php:

Use assertSame instead of assertArrayEquals in UIDGeneratorTest.
assertSame (and assertEqual) care about sortorder of the array,
and is perfectly sufficient in this case to check they array is correct.

if ( $puVersion !== '@package_version@' && version_compare( $puVersion, '3.7.0', '<' ) ) {
        die( "PHPUnit 3.7.0 or later required; you have {$puVersion}.\n" );
}

Change-Id: Ic32ab45110e4c4304ef046ae8d0e98c741255559