hg: jdk/sandbox: 8248605: Update --release 15 symbol information for JDK 15 build 31

[chris.hegarty at oracle.com]

Changeset: 6aacfbc575a8
Author:    darcy
Date:      2020-07-14 09:05 -0700
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/6aacfbc575a8

8248605: Update --release 15 symbol information for JDK 15 build 31
Reviewed-by: jlahoda, jjg

! make/data/symbols/java.base-F.sym.txt
! make/data/symbols/java.xml-F.sym.txt
! make/data/symbols/symbols