RFR: 8203031: segfaults from jvmti_AddToBootstrapClassLoaderSearch

[Alex Menkov]

Hi all,

Please review a fix for
bug: https://bugs.openjdk.java.net/browse/JDK-8203031
fix: http://cr.openjdk.java.net/~amenkov/addToBootstrapCLSearch/webrev/

The issue is a regression from JDK-8193213 (Make the UseAppCDS option 
obsolete)

FileMapInfo::current_info() is initialized by FileMapInfo ctor only when 
UseSharedSpaces == true:
Metaspace::global_initialize()
  -> MetaspaceShared::initialize_runtime_shared_and_meta_spaces
    -> new FileMapInfo()

--alex