polyfill 7.5 new assertions

[keradus]

https://github.com/sebastianbergmann/phpunit/blob/7.5/ChangeLog-7.5.md

Implemented #3340: Added assertEqualsCanonicalizing(), assertEqualsIgnoringCase(), assertEqualsWithDelta(), assertNotEqualsCanonicalizing(), assertNotEqualsIgnoringCase(), and assertNotEqualsWithDelta() as alternatives to using assertEquals() and assertNotEquals() with the $delta, $canonicalize, or $ignoreCase parameters

Implemented #3368: Added assertIsArray(), assertIsBool(), assertIsFloat(), assertIsInt(), assertIsNumeric(), assertIsObject(), assertIsResource(), assertIsString(), assertIsScalar(), assertIsCallable(), assertIsIterable(), assertIsNotArray(), assertIsNotBool(), assertIsNotFloat(), assertIsNotInt(), assertIsNotNumeric(), assertIsNotObject(), assertIsNotResource(), assertIsNotString(), assertIsNotScalar(), assertIsNotCallable(), assertIsNotIterable() as alternatives to assertInternalType() and assertNotInternalType()

Implemented #3422: Added assertStringContainsString(), assertStringContainsStringIgnoringCase(), assertStringNotContainsString(), and assertStringNotContainsStringIgnoringCase()