jvm-abi-gen: consider private type aliases to be public API

They can be referenced from public declarations right now.

^KT-54500 Fixed

plugins/jvm-abi-gen/src/org/jetbrains/kotlin/jvm/abi/JvmAbiMetadataProcessor.kt

@@ -155,11 +155,7 @@ private class AbiKmClassVisitor(delegate: KmClassVisitor) : KmClassVisitor(deleg
         return null
     }
 
-    override fun visitTypeAlias(flags: Flags, name: String): KmTypeAliasVisitor? {
-        if (!isPrivateDeclaration(flags))
-            return super.visitTypeAlias(flags, name)
-        return null
-    }
+    // TODO: do not serialize private type aliases once KT-17229 is fixed.
 
     override fun visitExtensions(type: KmExtensionType): KmClassExtensionVisitor? {
         val delegate = super.visitExtensions(type)
@@ -189,11 +185,7 @@ private class AbiKmPackageVisitor(delegate: KmPackageVisitor) : KmPackageVisitor
         return null
     }
 
-    override fun visitTypeAlias(flags: Flags, name: String): KmTypeAliasVisitor? {
-        if (!isPrivateDeclaration(flags))
-            return super.visitTypeAlias(flags, name)
-        return null
-    }
+    // TODO: do not serialize private type aliases once KT-17229 is fixed.
 
     override fun visitExtensions(type: KmExtensionType): KmPackageExtensionVisitor? {
         val delegate = super.visitExtensions(type)