git: openjdk/jdk: 8302879: doc/building.md update link to jtreg builds

[Christoph Langer]

Changeset: bb3dfd6a
Author:    George Adams <gdams at openjdk.org>
Committer: Christoph Langer <clanger at openjdk.org>
Date:      2023-02-20 21:58:55 +0000
URL:       https://git.openjdk.org/jdk/commit/bb3dfd6adbb58871bc7238107ed254831b22d48b

8302879: doc/building.md update link to jtreg builds

Reviewed-by: sgehwolf, clanger

! doc/building.html
! doc/building.md