With older kernels, printf.sh and bitmap.sh fail because they can't find
the respective test modules they are looking for.

Use modprobe dry run to check for missing test_XXX module. Error out with
the same error code as prime_numbers.sh.
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>