Make 'dashboard' target work when no tests are enabled

[bartlettroscoe]

Description

The current implementation of the TriBITS dashboard target will enable all packages if there are no package tests enabled. This problem is described in trilinos/Trilinos#11955 (comment) which shows:

...

**************************************************
*** Running all-at-once experimental dashboard ***
**************************************************

Trilinos_ENABLED_PACKAGES_LIST=


***
*** Run the dashboard command setting the list of packages
***

Running: env ... Trilinos_PACKAGES= ... <base-cmake-dir>/ctest -V -S <base-trilinos-dir>/cmake/tribits/ctest_driver/experimental_build_test.cmake

...

***
*** Determining what packages to enable based what was set in Trilinos_PACKAGES by the user ...
***

Setting Trilinos_ENABLE_ALL_PACKAGES=ON since Trilinos_PACKAGES_USER_SELECTED=''

...

Proposed solution

The proposed solution is to set <Project>_ENABLED_PACKAGES_LIST to <Project>_ENABLED_PACKAGES when <Project>_ENABLED_PACKAGES_LIST is empty due to no package tests being enabled.

Requirements

• Add test case for the dashboard target that does not have any tests enabled and enables just a subset of packages