test: complete console.assert() coverage

There is one condition in the `console.assert()` code that is not
tested currently. Add a test to confirm that `console.assert(false)`
does not include a `:` in its output.

PR-URL: #26827
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

test/parallel/test-console.js

@@ -193,6 +193,9 @@ console.assert(false, '%s should', 'console.assert', 'not throw');
 assert.strictEqual(errStrings[errStrings.length - 1],
                    'Assertion failed: console.assert should not throw\n');
 
+console.assert(false);
+assert.strictEqual(errStrings[errStrings.length - 1], 'Assertion failed\n');
+
 console.assert(true, 'this should not throw');
 
 console.assert(true);