Fix install testing refactor for inline builds

[jjwilke]

find_package should not be getting called for inline builds

This logic got lost in the install testing refactor. It was still working for Trilinos.

[ndellingwood]

Passed kokkos-dev-2 spot-check (minus intel, waiting on kokkos/kokkos#3383 to resolve compilation issues)

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PASSED TESTS
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clang-8.0-Cuda_OpenMP-release build_time=626 run_time=133
clang-8.0-Pthread_Serial-release build_time=201 run_time=125
clang-9.0.0-Pthread-release build_time=139 run_time=62
clang-9.0.0-Serial-release build_time=133 run_time=48
cuda-10.1-Cuda_OpenMP-release build_time=866 run_time=275
cuda-9.2-Cuda_Serial-release build_time=834 run_time=184
gcc-7.3.0-OpenMP-release build_time=145 run_time=45
gcc-7.3.0-Pthread-release build_time=119 run_time=57
gcc-8.3.0-Serial-release build_time=139 run_time=48
gcc-9.1-OpenMP-release build_time=180 run_time=48
gcc-9.1-Serial-release build_time=159 run_time=47