Fixed the ambiguous constructor issue in RemoteClassLoader.PSEUDO_BOOTSTRAP

The fix forces the usage of <ClassLoader> class in the second null argument.

Possible options:
* URLClassLoader(URL[] urls, ClassLoader parent)
* URLClassLoader(URL[] urls, AccessControlContext acc)

The fix significantly improves the code coverage in static analysis tools like Coverity (compilation units: 27% -> 100%). Coverity Scan project: https://scan.coverity.com/projects/2060?tab=Overview (not ready)

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>