[Bug]: Matchers ignore validating falsy values [runner] about stepci

[GaneshSelvarasu]

Additional note:

1. isNull matcher is also not behaving as expected. typeof given returns 'object' when the value of given is null. So, it shall be changed to

if ('isNull' in test) return test.isNull ? given === null : given !== null

2. isDefined shall be updated to

if ('isDefined' in test) return test.isDefined ? typeof given !== 'undefined' : typeof given === 'undefined'

[mishushakov]

Can you contribute a fix?

[GaneshSelvarasu]

Sure, I will create a PR and work on it.