git: openjdk/mobile: 8242155: Enhance automated macos signing tests

[duke]

Changeset: 83a1d70f
Author:    Andy Herrick <herrick at openjdk.org>
Date:      2020-04-10 16:21:12 +0000
URL:       https://git.openjdk.java.net/mobile/commit/83a1d70f

8242155: Enhance automated macos signing tests

Reviewed-by: asemenyuk, almatvee

! test/jdk/tools/jpackage/helpers/jdk/jpackage/test/Executor.java
! test/jdk/tools/jpackage/macosx/base/SigningBase.java