Remove obsolete test runner Xenial.

.github/workflows/ci.yml

@@ -140,69 +140,6 @@ jobs:
       - name: Test
         run: ../../../b2 toolset=$TOOLSET
         working-directory: ../boost-root/libs/type_traits/test
-  ubuntu-xenial:
-    runs-on: ubuntu-16.04
-    strategy:
-      fail-fast: false
-      matrix:
-        compiler: [ g++-5, g++-6, clang++-5.0, clang++-6.0 ]
-        standard: [ c++03, c++11, c++14, c++1z, gnu++03, gnu++11, gnu++14, gnu++1z ]
-    steps:
-      - uses: actions/checkout@v2
-        with:
-          fetch-depth: '0'
-      - uses: mstachniuk/ci-skip@v1
-        with:
-          commit-filter: '[skip ci];[ci skip];[CI SKIP];[SKIP CI];***CI SKIP***;***SKIP CI***;[windows];[Windows];[WINDOWS];[apple];[Apple];[APPLE]'
-          commit-filter-separator: ';'
-          fail-fast: true
-      - name: Set TOOLSET
-        run: echo ${{ matrix.compiler }} | awk '/^g/ { print "TOOLSET=gcc" } /^clang/ { print "TOOLSET=clang" }' >> $GITHUB_ENV
-      - name: Add repository
-        continue-on-error: true
-        id: addrepo
-        run: sudo apt-add-repository -y "ppa:ubuntu-toolchain-r/test"
-      - name: Retry Add Repo
-        continue-on-error: true
-        id: retry1
-        if: steps.addrepo.outcome=='failure'
-        run: sudo apt-add-repository -y "ppa:ubuntu-toolchain-r/test"
-      - name: Retry Add Repo 2
-        continue-on-error: true
-        id: retry2
-        if: steps.retry1.outcome=='failure'
-        run: sudo apt-add-repository -y "ppa:ubuntu-toolchain-r/test"
-      - name: Install packages
-        run: sudo apt install g++-5 g++-6 clang-5.0 clang-6.0 libgmp-dev libmpfr-dev libfftw3-dev
-      - name: Checkout main boost
-        run: git clone -b develop --depth 1 https://github.com/boostorg/boost.git ../boost-root
-      - name: Update tools/boostdep
-        run: git submodule update --init tools/boostdep
-        working-directory: ../boost-root
-      - name: Copy files
-        run: cp -r $GITHUB_WORKSPACE/* libs/type_traits
-        working-directory: ../boost-root
-      - name: Install deps
-        run: python tools/boostdep/depinst/depinst.py type_traits
-        working-directory: ../boost-root
-      - name: Bootstrap
-        run: ./bootstrap.sh
-        working-directory: ../boost-root
-      - name: Generate headers
-        run: ./b2 headers
-        working-directory: ../boost-root
-      - name: Generate user config
-        run: 'echo "using $TOOLSET : : ${{ matrix.compiler }} : <cxxflags>-std=${{ matrix.standard }} ;" > ~/user-config.jam'
-        working-directory: ../boost-root
-      - name: Config info install
-        run: ../../../b2 config_info_travis_install toolset=$TOOLSET
-        working-directory: ../boost-root/libs/config/test
-      - name: Config info
-        run: ./config_info_travis
-        working-directory: ../boost-root/libs/config/test
-      - name: Test
-        run: ../../../b2 toolset=$TOOLSET
-        working-directory: ../boost-root/libs/type_traits/test
   macos:
     runs-on: macos-latest
     strategy: