Remove i386 build tests

.gitlab-ci.yml

-job_gcc_386:
-  script:
-    - ./autogen.sh
-    - ./configure CXX="ccache g++" PYTHON=python3 --with-boost-python=py34 --prefix=$PWD/install --with-python-module-path=$PWD/install/site-packages --with-boost-coroutine=boost_coroutine
-    - CCACHE_BASEDIR=$PWD make $MAKEOPTS
-    - make install
-    - export PYTHONPATH=$PWD/install/site-packages
-    - cd doc; OMP_NUM_THREADS=1 python3 /usr/bin/sphinx-build -b doctest . build centrality.rst clustering.rst collection.rst inference.rst correlations.rst draw.rst faq.rst flow.rst generation.rst graph_tool.rst gt_format.rst index.rst modules.rst quickstart.rst spectral.rst stats.rst topology.rst util.rst
-  tags:
-    - i386
-
-job_gcc_py2_386:
-  script:
-    - ./autogen.sh
-    - ./configure CXX="ccache g++" PYTHON=python2  --prefix=$PWD/install --with-python-module-path=$PWD/install/site-packages --with-boost-coroutine=boost_coroutine
-    - CCACHE_BASEDIR=$PWD make $MAKEOPTS
-    - make install
-    - export PYTHONPATH=$PWD/install/site-packages
-    - cd doc; OMP_NUM_THREADS=1 python2 /usr/bin/sphinx-build -b doctest . build centrality.rst clustering.rst collection.rst inference.rst correlations.rst draw.rst faq.rst flow.rst generation.rst graph_tool.rst gt_format.rst index.rst modules.rst quickstart.rst spectral.rst stats.rst topology.rst util.rst
-  tags:
-    - i386
-
 job_gcc_amd64:
   script:
     - ./autogen.sh