JVM: remove StubClassBuilder and its usage

After legacy light classes were removed, the only remaining usage was in
KotlinLightClassBuilderFactory where we ran JVM backend in the
LIGHT_CLASSES mode, and that was only used from diagnostic tests to
report JVM backend diagnostics.

We don't actually need to build stubs here, so we can just use ASM's
class writer, which means that StubClassBuilder and all its dependencies
can be removed.

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/CliExtraDiagnosticsProvider.kt

@@ -48,7 +48,7 @@ object CliExtraDiagnosticsProvider {
             .ifEmpty { return Diagnostics.EMPTY }
 
         val context = (LightClassGenerationSupport.getInstance(project) as CliLightClassGenerationSupport).context
-        val (_, _, diagnostics) = extraJvmDiagnosticsFromBackend(
+        val (_, diagnostics) = extraJvmDiagnosticsFromBackend(
             facadeFqName.parent(),
             facadeCollection,
             ClassFilterForFacade,

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/LightClassDataProvider.kt

@@ -33,7 +33,7 @@ internal class LightClassDataProviderForClassOrObject(
         //force resolve companion for light class generation
         cliSupport.traceHolder.bindingContext.get(BindingContext.CLASS, classOrObject)?.companionObjectDescriptor
 
-        val (_, bindingContext, diagnostics) = extraJvmDiagnosticsFromBackend(
+        val (bindingContext, diagnostics) = extraJvmDiagnosticsFromBackend(
             packageFqName,
             listOf(file),
             ClassFilterForClassOrObject(classOrObject),