Exclude .kotlin_builtins files when proguarding kotlin-reflect.jar

Even though kotlin-annotations-jvm.jar itself doesn't contain those
files, ProGuard pulls them from the project dependency of
:kotlin-annotations-jvm on :core:builtins. They are already present in
kotlin-stdlib.jar and are thus not needed in kotlin-reflect.jar

libraries/reflect/build.gradle.kts

@@ -143,7 +143,7 @@ val proguard by task<ProGuardTask> {
     outputs.file(proguardOutput)
 
     injars(mapOf("filter" to "!META-INF/versions/**"), stripMetadata.outputs.files)
-    injars(mapOf("filter" to "!META-INF/**"), proguardAdditionalInJars)
+    injars(mapOf("filter" to "!META-INF/**,!**/*.kotlin_builtins"), proguardAdditionalInJars)
     outjars(proguardOutput)
 
     libraryjars(mapOf("filter" to "!META-INF/versions/**"), proguardDeps)