Add gdb_dejiagnu test script

This is the basic dejagnu test script. Currently it just generate
the board information, compile gdb/gdbserver and run make check.
It needs baseline and some other features later.

BUG=None
TEST=./gdb_dejagnu.py -c /extend/gamma/ -b lumpy -r 172.17.128.241
      It finishes the dejagnu run.

Change-Id: I81678926eda640bb5637e6e4dc540a7b9801b000
Reviewed-on: https://gerrit-int.chromium.org/35703
Reviewed-by: Han Shen <shenhan@google.com>
Commit-Queue: Yunlian Jiang <yunlian@google.com>
Tested-by: Yunlian Jiang <yunlian@google.com>
3 files changed