revamp kokoro macos jobs

tools/internal_ci/macos/grpc_master.cfg

@@ -15,7 +15,7 @@
 # Config file for the internal CI (in protobuf text format)
 
 # Location of the continuous shell script in repository.
-build_file: "grpc/tools/internal_ci/macos/grpc_master.sh"
+build_file: "grpc/tools/internal_ci/macos/grpc_run_tests_matrix.sh"
 timeout_mins: 240
 action {
   define_artifacts {
@@ -23,3 +23,8 @@ action {
     regex: "github/grpc/reports/**"
   }
 }
+
+env_vars {
+  key: "RUN_TESTS_FLAGS"
+  value: "-f basictests macos --internal_ci -j 2 --inner_jobs 4"
+}

tools/internal_ci/macos/grpc_master.sh

@@ -1,31 +0,0 @@
-#!/bin/bash
-# Copyright 2017 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 -ex
-
-# change to grpc repo root
-cd $(dirname $0)/../../..
-
-source tools/internal_ci/helper_scripts/prepare_build_macos_rc
-
-tools/run_tests/run_tests_matrix.py -f basictests macos --internal_ci -j 2 --inner_jobs 4 || FAILED="true"
-
-# kill port_server.py to prevent the build from hanging
-ps aux | grep port_server\\.py | awk '{print $2}' | xargs kill -9
-
-if [ "$FAILED" != "" ]
-then
-  exit 1
-fi