Use the latest releases of protoc and protobuf-java for ProtobufFuzzer (#13635)

Use the latest releases of protoc and protobuf-java for ProtobufFuzzer
instead of from protobuf github main branch, which is not gauranteed to
build or work at any time.

Author: shaod2

projects/protobuf-java/Dockerfile

@@ -26,8 +26,6 @@ ENV MVN $SRC/maven/apache-maven-3.6.3/bin/mvn
 
 RUN curl -L -O https://raw.githubusercontent.com/protobuf-c/protobuf-c/39cd58f5ff06048574ed5ce17ee602dc84006162/t/test-full.proto
 
-RUN git clone --depth 1 --recursive https://github.com/protocolbuffers/protobuf.git
-
 COPY build.sh $SRC
 COPY ProtobufFuzzer.java $SRC
 

projects/protobuf-java/build.sh

@@ -15,22 +15,21 @@
 #
 ################################################################################
 
-# Build protoc with default options.
+# Get the latest protoc binary release
 unset CFLAGS CXXFLAGS
-cd $SRC/protobuf/
-bazel build :protoc
-cp $SRC/protobuf/bazel-bin/protoc $SRC/protobuf/protoc
-export PROTOC="$SRC/protobuf/bazel-bin/protoc"
+mkdir -p $SRC/protobuf
+VERSION=$(curl --silent --fail "https://api.github.com/repos/protocolbuffers/protobuf/releases/latest" | jq -r '.tag_name' | sed 's/v//')
+PROTOC_ZIP="protoc-$VERSION-linux-x86_64.zip"
+curl --silent --fail -L -o "$SRC/$PROTOC_ZIP" "https://github.com/protocolbuffers/protobuf/releases/download/v$VERSION/$PROTOC_ZIP"
+unzip -o $PROTOC_ZIP -d $SRC/protobuf
+export PROTOC=$SRC/protobuf/bin/protoc
 
-
-# Build protobuf-java (requires protoc in source tree).
-cd $SRC/protobuf/java/
-cp $PROTOC $SRC/protobuf/src/
-MAVEN_ARGS="-Dmaven.test.skip=true -Djavac.src.version=15 -Djavac.target.version=15"
-$MVN package $MAVEN_ARGS
-CURRENT_VERSION=$($MVN org.apache.maven.plugins:maven-help-plugin:3.2.0:evaluate \
- -Dexpression=project.version -q -DforceStdout)
-cp "core/target/protobuf-java-$CURRENT_VERSION.jar" $OUT/protobuf-java.jar
+# Get the latest protobuf-java release
+JAVA_VERSION=$(curl -s "https://search.maven.org/solrsearch/select?q=g:com.google.protobuf+AND+a:protobuf-java&rows=1&wt=json" \
+  | jq -r '.response.docs[0].latestVersion')
+JAR_FILE="protobuf-java-$JAVA_VERSION.jar"
+curl --silent -L -o "$SRC/$JAR_FILE" "https://repo1.maven.org/maven2/com/google/protobuf/protobuf-java/$JAVA_VERSION/$JAR_FILE"
+cp $JAR_FILE $OUT/protobuf-java.jar
 
 # Compile test protos with protoc.
 cd $SRC/