fix: kokoro lint builds and lint script (GoogleCloudPlatform#1334)

Author: bshaffer

.kokoro/lint.cfg

@@ -7,6 +7,6 @@ env_vars: {
 }
 
 env_vars: {
-    key: "RUN_CS_CHECK"
-    value: "true"
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/php-docs-samples/testing/run_cs_check.sh"
 }

.kokoro/lint.sh

@@ -15,7 +15,3 @@ env_vars: {
     key: "GOOGLE_ALT_CREDENTIALS_FILENAME"
     value: "service-account-kokoro1.json"
 }
-env_vars: {
-    key: "RUN_CS_CHECK"
-    value: "true"
-}

.kokoro/php74.cfg

@@ -50,11 +50,6 @@ mkdir -p build/logs
 
 export PULL_REQUEST_NUMBER=$KOKORO_GITHUB_PULL_REQUEST_NUMBER
 
-# Run code standards check when appropriate
-if [ "${RUN_CS_CHECK}" = "true" ]; then
-  bash testing/run_cs_check.sh
-fi
-
 # If we are running REST tests, disable gRPC
 if [ "${RUN_REST_TESTS_ONLY}" = "true" ]; then
   GRPC_INI=$(php -i | grep grpc.ini | sed 's/^Additional .ini files parsed => //g' | sed 's/,*$//g' )

.kokoro/system_tests.sh

@@ -23,5 +23,7 @@ elif [ -f "./php-cs-fixer" ]; then
     PHP_CS_FIXER="./php-cs-fixer"
 fi
 
-DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
-$PHP_CS_FIXER fix --dry-run --diff --config="$DIR/../.php_cs.dist" --path-mode=intersection .
+PROJECT_ROOT="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )/.."
+DIR="${1:-$PROJECT_ROOT}"
+
+$PHP_CS_FIXER fix --dry-run --diff --config="${PROJECT_ROOT}/.php_cs.dist" --path-mode=intersection $DIR