Fix error in wizard when creating module-info file (GH4628)

[neilcsmith-net]

Fixes a spurious error message that the file already exists shown when creating a module-info file, as reported in #4628 This is actually an IndexOutOfBoundsException caused by javac changes (ModuleTree no longer returned from getTypeDecls() but available from added getModule()).

The second commit filters out the created module name from the list of added requires. This is an older issue that became visible again that shows a cyclic dependency error.