Make ARM64 C/C++ bazel tests greener (#26518)

* add no_arm64 tag to resolver_component_tests_runner_invoker tests

* skip no_arm64 tests when running on arm64

* increase kokoro jobs timeout for ARM64 C/C++ bazel tests

* use 8 core instance for arm64 bazel C/C++ tests

test/cpp/naming/generate_resolver_component_tests.bzl

@@ -85,5 +85,8 @@ def generate_resolver_component_tests():
                 "--test_bin_name=resolver_component_test%s" % unsecure_build_config_suffix,
                 "--running_under_bazel=true",
             ],
-            tags = ["no_windows", "no_mac"],
+            # The test is highly flaky on AWS workers that we use for running ARM64 tests.
+            # The "no_arm64" tag can be used to skip it.
+            # (see https://github.com/grpc/grpc/issues/25289).
+            tags = ["no_windows", "no_mac", "no_arm64"],
         )

tools/internal_ci/linux/aws/grpc_aws_bazel_test_c_cpp.cfg

@@ -15,8 +15,8 @@
 # Config file for the internal CI (in protobuf text format)
 
 # Location of the continuous shell script in repository.
-build_file: "grpc/tools/internal_ci/linux/aws/grpc_aws_run_remote_test.sh"
-timeout_mins: 90
+build_file: "grpc/tools/internal_ci/linux/aws/grpc_aws_run_remote_test_8core.sh"
+timeout_mins: 120
 before_action {
     fetch_keystore {
         keystore_resource {

tools/internal_ci/linux/aws/grpc_aws_run_remote_test.sh

@@ -49,7 +49,8 @@ sudo apt update && sudo apt install -y jq
 # ubuntu 18.04 lts(arm64)
 # https://aws.amazon.com/amazon-linux-ami/
 AWS_MACHINE_IMAGE=ami-026141f3d5c6d2d0c
-AWS_INSTANCE_TYPE=t4g.xlarge
+# use 4-core instance by default
+AWS_INSTANCE_TYPE=${AWS_INSTANCE_TYPE:-t4g.xlarge}
 AWS_SECURITY_GROUP=sg-021240e886feba750
 # Max allowed lifespan of the AWS instance. After this period of time, the instance will
 # self-terminate (delete itself). This is very important to ensure that there will

tools/internal_ci/linux/aws/grpc_aws_run_remote_test_8core.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+# Copyright 2021 The 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.
+
+set -e
+
+AWS_INSTANCE_TYPE="t4g.2xlarge" "$(dirname $0)/grpc_aws_run_remote_test.sh"

tools/internal_ci/linux/aws/grpc_bazel_test_c_cpp_aarch64.sh

@@ -26,4 +26,4 @@ cd grpc
 python tools/run_tests/start_port_server.py
 
 # test gRPC C/C++ with bazel
-tools/bazel test --config=opt --test_output=errors --test_tag_filters=-no_linux --build_tag_filters=-no_linux --flaky_test_attempts=1 --runs_per_test=1 //test/...
+tools/bazel test --config=opt --test_output=errors --test_tag_filters=-no_linux,-no_arm64 --build_tag_filters=-no_linux,-no_arm64 --flaky_test_attempts=1 --runs_per_test=1 //test/...