[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/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ClassCodegen.kt

@@ -446,7 +446,7 @@ class ClassCodegen private constructor(
                     ?: error("Class in a non-static initializer found, but container has no constructors: ${containerClass.render()}")
             } else parentFunction
             if (enclosingFunction != null || irClass.isAnonymousInnerClass) {
-                val method = enclosingFunction?.let(context.methodSignatureMapper::mapAsmMethod)
+                val method = enclosingFunction?.let(context.methodSignatureMapper::mapAsmMethod)?.takeIf { it.name != "<clinit>" }
                 visitor.visitOuterClass(parentClassCodegen!!.type.internalName, method?.name, method?.descriptor)
             }
         }