The Valhalla repository contains an experimental support for primitive classes in the JPDA (Java Platform Debugger Architecture) that has been implemented in the following CRs: JDK-8232058, JDK-8211027, JDK-8211026, JDK-8211028, JDK-8232785.
As an anticipation of the merge of Valhalla code into mainline, this code has to be removed because it contains modification to JDI, JDWP and JVMTI that are not part of the current specification of these APIs.