Generate 'Deprecated' annotation on invisible companion object field

Design decision: if the field for a companion object should have
non-public visibility, generate it with @Deprecated annotation in
language version 1.2.

TODO: generate it with proper visibility in 1.3 and later.

KT-11567 Companion object INSTANCE field more visible than companion object class itself

compiler/testData/codegen/bytecodeListing/invisibleCompanionObject.kt

@@ -0,0 +1,13 @@
+// LANGUAGE_VERSION: 1.2
+
+class TestPrivateCompanion {
+    private companion object Test
+}
+
+open class TestProtectedCompanion {
+    protected companion object Test
+}
+
+class TestInternalCompanion {
+    internal companion object Test
+}