Removed jessie-based distribtest (#29029)

* Removed jessie-based distribtest

* Update by review

tools/dockerfile/distribtest/cpp_jessie_x64/Dockerfile

@@ -1,36 +0,0 @@
-# Copyright 2016 gRPC authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-FROM debian:jessie
-RUN sed -i '/deb http:\/\/deb.debian.org\/debian jessie-updates main/d' /etc/apt/sources.list
-
-# Install packages needed for gRPC and protobuf
-RUN apt-get update && apt-get install -y \
-      autoconf \
-      automake \
-      build-essential \
-      curl \
-      git \
-      g++ \
-      libtool \
-      make \
-      pkg-config \
-      unzip && apt-get clean
-
-RUN echo "deb http://archive.debian.org/debian jessie-backports main" | tee /etc/apt/sources.list.d/jessie-backports.list
-RUN echo 'Acquire::Check-Valid-Until "false";' > /etc/apt/apt.conf
-RUN sed -i '/deb http:\/\/deb.debian.org\/debian jessie-updates main/d' /etc/apt/sources.list
-RUN apt-get update && apt-get install -t jessie-backports -y cmake && apt-get clean
-
-CMD ["bash"]

tools/dockerfile/distribtest/csharp_jessie_x64/Dockerfile

@@ -1,31 +0,0 @@
-# Copyright 2015 gRPC authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-FROM debian:jessie
-
-RUN apt-get update && apt-get install -y apt-transport-https && apt-get clean
-
-RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
-RUN echo "deb https://download.mono-project.com/repo/debian stable-jessie main" | tee /etc/apt/sources.list.d/mono-official-stable.list
-
-RUN apt-get update && apt-get install -y \
-    mono-devel \
-    nuget \
-    && apt-get clean
-
-RUN apt-get update && apt-get install -y unzip && apt-get clean
-
-# Make sure the mono certificate store is up-to-date to prevent issues with nuget restore
-RUN apt-get update && apt-get install -y curl && apt-get clean
-RUN curl https://curl.haxx.se/ca/cacert.pem > ~/cacert.pem && cert-sync ~/cacert.pem && rm -f ~/cacert.pem

tools/run_tests/artifacts/distribtest_targets.py

@@ -353,12 +353,12 @@ def targets():
     """Gets list of supported targets"""
     return [
         # C++
+        CppDistribTest('linux', 'x64', 'stretch', 'cmake', presubmit=True),
         CppDistribTest('linux',
                        'x64',
-                       'jessie',
+                       'stretch',
                        'cmake_as_submodule',
                        presubmit=True),
-        CppDistribTest('linux', 'x64', 'stretch', 'cmake', presubmit=True),
         CppDistribTest('linux',
                        'x64',
                        'stretch',
@@ -395,8 +395,7 @@ def targets():
                        testcase='cmake_as_externalproject',
                        presubmit=True),
         # C#
-        CSharpDistribTest('linux', 'x64', 'jessie', presubmit=True),
-        CSharpDistribTest('linux', 'x64', 'stretch'),
+        CSharpDistribTest('linux', 'x64', 'stretch', presubmit=True),
         CSharpDistribTest('linux',
                           'x64',
                           'stretch',