langtools_custom doesn't work correctly with multiple testcases

[sophia-guo]

When use generated rerun langtools_custom target link https://ci.adoptium.net/job/Grinder/parambuild/?SDK_RESOURCE=upstream&TARGET=langtools_custom&BASE_DOCKER_REGISTRY_CREDENTIAL_ID=&TEST_FLAG=&UPSTREAM_TEST_JOB_NAME=&DOCKER_REQUIRED=false&ACTIVE_NODE_TIMEOUT=5&VENDOR_TEST_DIRS=&EXTRA_DOCKER_ARGS=&TKG_OWNER_BRANCH=adoptium%3Amaster&OPENJ9_SYSTEMTEST_OWNER_BRANCH=eclipse%3Amaster&PLATFORM=arm_linux&GENERATE_JOBS=false&KEEP_REPORTDIR=true&PERSONAL_BUILD=false&DOCKER_REGISTRY_DIR=&ADOPTOPENJDK_REPO=https%3A%2F%2Fgithub.com%2Fadoptium%2Faqa-tests.git&RERUN_ITERATIONS=0&SETUP_JCK_RUN=false&DOCKER_REGISTRY_URL_CREDENTIAL_ID=&LABEL=&EXTRA_OPTIONS=&CUSTOMIZED_SDK_URL=&BUILD_IDENTIFIER=&JENKINS_KEY=&ADOPTOPENJDK_BRANCH=v1.0.5-release&LIGHT_WEIGHT_CHECKOUT=false&USE_JRE=false&ARTIFACTORY_SERVER=&KEEP_WORKSPACE=false&USER_CREDENTIALS_ID=&JDK_VERSION=8&DOCKER_REGISTRY_URL=&ITERATIONS=1&VENDOR_TEST_REPOS=&JDK_REPO=https%3A%2F%2Fgithub.com%2Fadoptium%2Faarch32-jdk8u&JCK_GIT_BRANCH=master&OPENJ9_BRANCH=master&OPENJ9_SHA=&JCK_GIT_REPO=&VENDOR_TEST_BRANCHES=&OPENJ9_REPO=https%3A%2F%2Fgithub.com%2Feclipse-openj9%2Fopenj9.git&UPSTREAM_JOB_NAME=build-scripts%2Fjobs%2Frelease%2Fjobs%2Fjdk8u%2Fjdk8u-release-linux-arm-temurin&CLOUD_PROVIDER=&CUSTOM_TARGET=tools%2Fjavac%2Flambda%2FmostSpecific%2FStructuralMostSpecificTest.java+tools%2Fjavac%2Ffile%2Fzip%2FT6836682.java+tools%2Fjavac%2Flambda%2Fintersection%2FIntersectionTargetTypeTest.java+tools%2Fjavac%2Flambda%2Fbridge%2FTestMetafactoryBridges.java&VENDOR_TEST_SHAS=&JDK_BRANCH=&LABEL_ADDITION=&ARTIFACTORY_REPO=&ARTIFACTORY_ROOT_DIR=&UPSTREAM_TEST_JOB_NUMBER=&DOCKERIMAGE_TAG=&JDK_IMPL=hotspot&TEST_TIME=120&SSH_AGENT_CREDENTIAL=&AUTO_DETECT=true&SLACK_CHANNEL=aqavit-bot&DYNAMIC_COMPILE=false&RELATED_NODES=&ADOPTOPENJDK_SYSTEMTEST_OWNER_BRANCH=adoptium%3Amaster&APPLICATION_OPTIONS=&CUSTOMIZED_SDK_URL_CREDENTIAL_ID=eclipse_temurin_bot_email_and_token&ARCHIVE_TEST_RESULTS=false&OPENJDK_SHA=&NUM_MACHINES=&TRSS_URL=&RERUN_FAILURE=true&BUILD_LIST=openjdk&USE_TESTENV_PROPERTIES=true&ADDITIONAL_ARTIFACTS_REQUIRED=&UPSTREAM_JOB_NUMBER=16&STF_OWNER_BRANCH=adoptium%3Amaster&TIME_LIMIT=25&JVM_OPTIONS=&PARALLEL=None from https://ci.adoptium.net/job/Test_openjdk8_hs_sanity.openjdk_arm_linux/662/ the grinder https://ci.adoptium.net/job/Grinder/12640/ didn't run the langtools_custom correctly with multiple testcases. Can only run one testcase, multiple testcases weren't parsed with correct test path.