Remove SystemDictionaryShared::clone_dumptime_tables()

This function was add in JDK-8264735 "Make dynamic dump repeatable". It was necessary because each time we used "jcmd $PID VM.cds dynamic_dump" to connect to a JVM process, the pointers inside SystemDictionaryShared::_dumptime_table would be patched by the relocation code, making it impossible to dump repeatedly in the same process.

Since JDK-8307567 "Avoid relocating global roots to metaspaceObjs in CDS dump", the pointers in _dumptime_table are no longer patched during dumping. Therefore, the cloning/restoring logic is no longer necessary and can be removed.