Extend and improve SyntaxConformance and other api tests to use operator other then (=, IN)

In addition two changes has been made in tests/phpunit/api/v3/SyntaxConformanceTest.php where-
1) ContributionSoft.pcp_id cannot be updated as it needs existing pcp.id to match with the value passed https://github.com/monishdeb/civicrm-core/commit/7d543448c609a05fc006bd40fd431b2fa83a2ec7#diff-bddbee60cb233dfdfeeb835d1614fcdeR519
2) Nonexistent Event.id check is being bypassed for now as it pseudo property is associated with it and it eventually lookout for existing for event.id which is ignored by testAcceptsOnlyID_get and leads to test failure