IJ-CR-151018 [java-inspection] IDEA-363979 Conflicts with on-demand and module imports

- introduce enum for conflicts
- add annotations
- direct implementation isOnDemand for PsiImportModuleStatementImpl

(cherry picked from commit a116b4952b6498e98740d115cace170512d0d59a)

GitOrigin-RevId: 27f28ecf92cd147f13c5e5a6ebe123b7962aa4f1

java/java-psi-impl/src/com/intellij/psi/impl/source/PsiImportModuleStatementImpl.java

@@ -118,6 +118,11 @@ public class PsiImportModuleStatementImpl extends PsiImportStatementBaseImpl imp
     return ref != null ? ref.resolve() : null;
   }
 
+  @Override
+  public boolean isOnDemand() {
+    return true;
+  }
+
   @Override
   public String toString() {
     return "PsiImportModuleStatement";