We want to verify that ctest_start(APPEND) works the way we expect it to.

ctest_start(Experimental)
ctest_configure()
ctest_submit(PARTS Configure)

in one script, and then execute subsequent scripts that call:

ctest_start(APPEND)
ctest_build()
ctest_submit(PARTS Build)

(etc.)

The goal here is to make sure that all of these submissions result in a single row on CDash.