add child process test case.
Squashed 'extenal/shmdb/' changes from d7fc4b7..ff41309

ff41309 add the condition of putting in child process and getting in parent process.
b6992f7 redefine the type of shmaddr in STHashShareHandle.
3a46153 fixed the problem of get prime when the input parameter is less than 12.

git-subtree-dir: extenal/shmdb
git-subtree-split: ff4130951c9c0ecd2b8ba78743e357a133a120bb
Merge commit 'efcd0efe535dd9e15b184e7618b298a77a1666e3'