GDB tests: Factor out duplication in nacl.scons file
GDB tests: Factor out duplication in nacl.scons file

Introduce an AddGdbTest() function.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3739
TEST=gdb_tests
R=bradnelson@google.com

Review URL: https://codereview.chromium.org/144623002

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@12651 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client