8151623: Zap freed Metaspace chunks in non-product binaries

Reviewed-by: stefank, jmasa

hotspot/src/share/vm/utilities/globalDefinitions.hpp

@@ -1056,6 +1056,7 @@ const int      badHandleValue   = 0xBC;                     // value used to zap
 const int      badResourceValue = 0xAB;                     // value used to zap resource area
 const int      freeBlockPad     = 0xBA;                     // value used to pad freed blocks.
 const int      uninitBlockPad   = 0xF1;                     // value used to zap newly malloc'd blocks.
+const juint    uninitMetaWordVal= 0xf7f7f7f7;               // value used to zap newly allocated metachunk
 const intptr_t badJNIHandleVal  = (intptr_t) UCONST64(0xFEFEFEFEFEFEFEFE); // value used to zap jni handle area
 const juint    badHeapWordVal   = 0xBAADBABE;               // value used to zap heap after GC
 const juint    badMetaWordVal   = 0xBAADFADE;               // value used to zap metadata heap after GC