JVM: Don't generate accessors to companions in earlier language versions

compiler/testData/codegen/bytecodeText/companion/privateCompanionObjectAccessors_after.kt

@@ -0,0 +1,13 @@
+// !LANGUAGE: +ProperVisibilityForCompanionObjectInstanceField
+// IGNORE_BACKEND: JVM_IR
+// ^ TODO implement ProperVisibilityForCompanionObjectInstanceField feature support in JMV_IR
+
+class Host {
+    private companion object {
+        fun foo() = 1
+    }
+
+    fun test() = { foo() }
+}
+
+// 1 synthetic access\$

compiler/testData/codegen/bytecodeText/companion/privateCompanionObjectAccessors_before.kt

@@ -0,0 +1,11 @@
+// !LANGUAGE: -ProperVisibilityForCompanionObjectInstanceField
+
+class Host {
+    private companion object {
+        fun foo() = 1
+    }
+
+    fun test() = { foo() }
+}
+
+// 0 synthetic access\$