JDK 16 RFR of JDK-8245588: Update --release 15 symbol information for JDK 15 build 27

[Joe Darcy]

Hello,

Please review updating JDK 16's --release 15 information for JDK 15 b27:

    http://cr.openjdk.java.net/~darcy/8245588.0/

Thanks,

-Joe