RFR(S) 8246181: Avoid walking SymbolTable during -Xshare:dump

[Yumin Qi]

Hi, Please review

Bug: https://bugs.openjdk.java.net/browse/JDK-8246181

Webrev:http://cr.openjdk.java.net/~minqi/2020/8246181/webrev-00/


Summary: This is a little different from the bug suggested 
implementation. To avoid working the SymbolTable during dump, the symbol 
is added to a global array when it is created, 
SymbolTable::do_add_if_needed. The symbol only created once during its 
lifetime. There is just little performance overhead for runtime.


Tests: local jtreg on runtime/cds/appcds for debug/release.

mach5: tier1,tier2,tier4


Thanks

Yumin