test(astnode.js): avoid skipping tests having node.js inside

This commit makes the test suite run test/specs/jsdoc/src/astnode.js

It was previously skipped because of the runtime being node and
astnode.js containing "node"..

I even wonder if its still relevant to try to support different
runtime, but that's for another PR I guess.

test/spec-collection.js

@@ -52,7 +52,7 @@ function isValidSpec(file, matcher) {
             // ...match the matcher
             matcher.test( path.basename(file) ) &&
             // ...be relevant to the current runtime
-            file.indexOf(skipPath) === -1;
+            file.indexOf('/' + skipPath + '/') === -1;
     }
     catch (e) {
         result = false;