hg: jdk/sandbox: 8212587: equals in MakeBase does not handle empty strings correctly

[chris.hegarty at oracle.com]

Changeset: 0dac3131b0fd
Author:    ihse
Date:      2018-10-18 09:19 +0200
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/0dac3131b0fd

8212587: equals in MakeBase does not handle empty strings correctly
Reviewed-by: erikj

! make/common/MakeBase.gmk
! test/make/TestMakeBase.gmk