hg: code-tools/jtreg: 7902089: build-all.sh should honor BUILD_NUMBER from environment (and use a reasonable default)

[jonathan.gibbons at oracle.com]

Changeset: 8ca4454391c8
Author:    jjg
Date:      2017-12-22 11:22 -0800
URL:       http://hg.openjdk.java.net/code-tools/jtreg/rev/8ca4454391c8

7902089: build-all.sh should honor BUILD_NUMBER from environment (and use a reasonable default)
Contributed-by: volker.simonis at gmail.com

! make/build-all.sh