chore: Remove local install repo from source test

Author: lqiu96

.github/workflows/downstream_protobuf_compatibility_check_nightly.yaml

@@ -63,7 +63,7 @@ jobs:
       - name: Print Protobuf-Java testing version
         run: echo "Testing with Protobuf-Java v${{ matrix.protobuf-version }}"
       - name: Perform downstream source compatibility testing
-        run: REPOS_UNDER_TEST="${{ matrix.repo }}" PROTOBUF_RUNTIME_VERSION="${{ matrix.protobuf-version }}" REPOS_INSTALLED_LOCALLY="true" ./.kokoro/nightly/downstream-protobuf-source-compatibility.sh
+        run: REPOS_UNDER_TEST="${{ matrix.repo }}" PROTOBUF_RUNTIME_VERSION="${{ matrix.protobuf-version }}" ./.kokoro/nightly/downstream-protobuf-source-compatibility.sh
       - name: Perform downstream binary compatibility testing
         run: REPOS_UNDER_TEST="${{ matrix.repo }}" PROTOBUF_RUNTIME_VERSION="${{ matrix.protobuf-version }}" REPOS_INSTALLED_LOCALLY="true" ./.kokoro/nightly/downstream-protobuf-binary-compatibility.sh
 

.kokoro/nightly/downstream-protobuf-source-compatibility.sh

@@ -15,13 +15,9 @@
 
 set -eo pipefail
 
-# There are three Env Vars that this script uses.
+# There are two Env Vars that this script uses.
 # 1. (Required) REPOS_UNDER_TEST: Comma separate list of the repo names
 # 2. (Required) PROTOBUF_RUNTIME_VERSION: Protobuf runtime version to test again
-# 3. REPOS_INSTALLED_LOCALLY: Flag (if set to "true) will determine if the repo
-# needs to be cloned from github and re-installed locally to the m2. If the artifact
-# is already installed locally, this saves time as the artifact is not again compiled
-# and built.
 
 # Comma-delimited list of repos to test with the local java-shared-dependencies
 if [ -z "${REPOS_UNDER_TEST}" ]; then
@@ -38,16 +34,13 @@ if [ -z "${PROTOBUF_RUNTIME_VERSION}" ]; then
 fi
 
 for repo in ${REPOS_UNDER_TEST//,/ }; do # Split on comma
-  if [ "${REPOS_INSTALLED_LOCALLY}" != "true" ]; then
-    # Perform source-compatibility testing on main (latest changes)
-    git clone "https://github.com/googleapis/$repo.git" --depth=1
-  fi
-
+  # Perform source-compatibility testing on main (latest changes)
+  git clone "https://github.com/googleapis/$repo.git" --depth=1
   pushd "$repo"
 
   # Compile the Handwritten Library with the Protobuf-Java version to test source compatibility
   # Run unit tests to help check for any behavior differences (dependant on coverage)
-  mvn compile -B -V -ntp \
+  mvn test -B -V -ntp \
       -Dclirr.skip=true \
       -Denforcer.skip=true \
       -Dmaven.javadoc.skip=true \