[Analysis API] Generify 'KtCodeFragmentModule' to support ordinary files

This commit introduces dangling file modules, which may be either
code fragments or ordinary Kotlin files. As before, code fragments are
analyzed against some context element, however ordinary files only
have a context module.

Code fragments can also have a dangling file module as a contextual one,
including other code fragment. This is done to support potential usages
in completion, intentions and refactorings.

analysis/symbol-light-classes/src/org/jetbrains/kotlin/light/classes/symbol/SymbolKotlinAsJavaSupport.kt

@@ -194,10 +194,13 @@ class SymbolKotlinAsJavaSupport(project: Project) : KotlinAsJavaSupportBase<KtMo
 
     private fun KtElement.isFromSourceOrLibraryBinary(): Boolean = getModuleIfSupportEnabled()?.isFromSourceOrLibraryBinary() == true
 
-    private fun KtModule.isFromSourceOrLibraryBinary() = when (this) {
-        is KtSourceModule -> true
-        is KtLibraryModule -> true
-        else -> false
+    private fun KtModule.isFromSourceOrLibraryBinary(): Boolean {
+        return when (this) {
+            is KtSourceModule -> true
+            is KtLibraryModule -> true
+            is KtDanglingFileModule -> contextModule.isFromSourceOrLibraryBinary()
+            else -> false
+        }
     }
 }