IJ file type optimizations based on extension

#KTIJ-21668

Merge-request: KT-MR-6288
Merged-by: Vladimir Dolzhenko <Vladimir.Dolzhenko@jetbrains.com>

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/modules/JavaModule.kt

@@ -90,7 +90,7 @@ interface JavaModule {
             get() = moduleInfo.moduleName
 
         override val isSourceModule: Boolean
-            get() = moduleInfoFile.fileType == JavaFileType.INSTANCE
+            get() = moduleInfoFile.extension == JavaFileType.DEFAULT_EXTENSION || moduleInfoFile.fileType == JavaFileType.INSTANCE
 
         override fun exports(packageFqName: FqName): Boolean {
             return moduleInfo.exports.any { (fqName, toModules) ->