re-enable debugger tests in travis but run them with non-compiled Cython

.travis.yml

@@ -22,13 +22,12 @@ before_install:
   - sudo apt-get install gdb python$( python -c 'import sys; print("%d.%d" % sys.version_info[:2])' )-dbg || true
   - dpkg -l | grep gdb || true
 
-install:
-  - CFLAGS="-O2 -ggdb -Wall -Wextra" python setup.py build
-  - CFLAGS="-O2 -ggdb -Wall -Wextra" python setup.py build_ext -i
+install: CFLAGS="-O2 -ggdb -Wall -Wextra" python setup.py build
 
 script:
   - PYTHON_DBG="python$( python -c 'import sys; print("%d.%d" % sys.version_info[:2])' )-dbg"
-  - # if $PYTHON_DBG -V >&2; then CFLAGS="-O0 -ggdb" $PYTHON_DBG runtests.py -vv Debugger --backends=$BACKEND; fi
+  - if $PYTHON_DBG -V >&2; then CFLAGS="-O0 -ggdb" $PYTHON_DBG runtests.py -vv Debugger --backends=$BACKEND; fi
+  - CFLAGS="-O2 -ggdb -Wall -Wextra" python setup.py build_ext -i
   - CFLAGS="-O0 -ggdb -Wall -Wextra" python runtests.py -vv -x Debugger --backends=$BACKEND
 
 matrix: