[JVM IR] Do not generate clinit as enclosing method.

The JVM and newer Android runtimes treats that the same as if
there is no enclosing method. However, older Android runtimes
for Android 5 and 6 throw exceptions on reflective access
and even older runtimes have different behavior. To avoid
those issues, exclude <clinit> from enclosing method attributes.

^ KT-48754 Fixed

compiler/testData/codegen/bytecodeListing/fileClassWithPrivateDeclarationsOnly_after.txt

@@ -1,7 +1,7 @@
 @kotlin.Metadata
 final class FileClassWithPrivateDeclarationsOnly_afterKt$b$2 {
     // source: 'fileClassWithPrivateDeclarationsOnly_after.kt'
-    enclosing method FileClassWithPrivateDeclarationsOnly_afterKt.<clinit>()V
+    enclosing class FileClassWithPrivateDeclarationsOnly_afterKt
     public final static field INSTANCE: FileClassWithPrivateDeclarationsOnly_afterKt$b$2
     inner (anonymous) class FileClassWithPrivateDeclarationsOnly_afterKt$b$2
     static method <clinit>(): void