8150900: Implement diagnostic_pd
Reviewed-by: twisti, gziemski, kevinw

8073500: Prevent certain commercial flags from being changed at runtime
Summary: Implement new writeable mechanism for flag control
Reviewed-by: coleenp, iklam

8122937: [JEP 245] Validate JVM Command-Line Flag Arguments.
Summary: Validate the arguments to all JVM command-line flags so as to avoid crashes, and ensure that appropriate error messages are displayed when they are invalid.
Reviewed-by: ddmitriev, dholmes, kbarrett, drwhite, brutisso, coleenp

8079792: GC directory structure cleanup
Reviewed-by: brutisso, stefank, david