8164011: --patch-module support for CDS

Allows the use of the --patch-module vm option with CDS. However, classes found in --patch-module during dump time will not be archived.

Reviewed-by: iklam, dcubed, lfoltan

hotspot/src/share/vm/memory/filemap.hpp

@@ -155,6 +155,7 @@ public:
     // loading failures during runtime.
     int _classpath_entry_table_size;
     size_t _classpath_entry_size;
+    int    _num_patch_mod_prefixes;   // number of --patch-module entries
     SharedClassPathEntry* _classpath_entry_table;
 
     char* region_addr(int idx);