install cmake in CXX test images

templates/tools/dockerfile/cmake.include

@@ -0,0 +1,5 @@
+#=================
+# Install cmake
+# Note that this step should be only used for distributions that have new enough cmake to satisfy gRPC's cmake version requirement.
+
+RUN apt-get update && apt-get install -y cmake && apt-get clean

templates/tools/dockerfile/test/cxx_buster_x64/Dockerfile.template

@@ -20,6 +20,7 @@
   <%include file="../../python_deps.include"/>
   <%include file="../../gcp_api_libraries.include"/>
   <%include file="../../cxx_deps.include"/>
+  <%include file="../../cmake.include"/>
   <%include file="../../run_tests_addons.include"/>
   
   # Define the default command.

templates/tools/dockerfile/test/cxx_ubuntu1604_x64/Dockerfile.template

@@ -20,6 +20,7 @@
   <%include file="../../python_deps.include"/>
   <%include file="../../gcp_api_libraries.include"/>
   <%include file="../../cxx_deps.include"/>
+  <%include file="../../cmake.include"/>
   <%include file="../../run_tests_addons.include"/>
   
   # The clang-3.6 symlink for the default clang version was added

templates/tools/dockerfile/test/cxx_ubuntu1804_x64/Dockerfile.template

@@ -20,6 +20,7 @@
   <%include file="../../python_deps.include"/>
   <%include file="../../gcp_api_libraries.include"/>
   <%include file="../../cxx_deps.include"/>
+  <%include file="../../cmake.include"/>
   <%include file="../../run_tests_addons.include"/>
   
   # Define the default command.

tools/dockerfile/test/cxx_buster_x64/Dockerfile

@@ -72,6 +72,12 @@ RUN pip install --upgrade google-api-python-client oauth2client
 # C++ dependencies
 RUN apt-get update && apt-get -y install libgflags-dev libgtest-dev libc++-dev clang && apt-get clean
 
+#=================
+# Install cmake
+# Note that this step should be only used for distributions that have new enough cmake to satisfy gRPC's cmake version requirement.
+
+RUN apt-get update && apt-get install -y cmake && apt-get clean
+
 
 RUN mkdir /var/local/jenkins
 

tools/dockerfile/test/cxx_ubuntu1604_x64/Dockerfile

@@ -72,6 +72,12 @@ RUN pip install --upgrade google-api-python-client oauth2client
 # C++ dependencies
 RUN apt-get update && apt-get -y install libgflags-dev libgtest-dev libc++-dev clang && apt-get clean
 
+#=================
+# Install cmake
+# Note that this step should be only used for distributions that have new enough cmake to satisfy gRPC's cmake version requirement.
+
+RUN apt-get update && apt-get install -y cmake && apt-get clean
+
 
 RUN mkdir /var/local/jenkins
 

tools/dockerfile/test/cxx_ubuntu1804_x64/Dockerfile

@@ -72,6 +72,12 @@ RUN pip install --upgrade google-api-python-client oauth2client
 # C++ dependencies
 RUN apt-get update && apt-get -y install libgflags-dev libgtest-dev libc++-dev clang && apt-get clean
 
+#=================
+# Install cmake
+# Note that this step should be only used for distributions that have new enough cmake to satisfy gRPC's cmake version requirement.
+
+RUN apt-get update && apt-get install -y cmake && apt-get clean
+
 
 RUN mkdir /var/local/jenkins