KAFKA-9034: Use double quotes around $JAVA_HOME evn variable

This allows kafka tools to work on Cygwin where $JAVA_HOME typically contains a space (e.g. "C:\Program Files\Java\jdkXXX")

Author: sebwills <sw@sebwills.com>

Reviewers: Ron Dagostino <rdagostino@confluent.io>, Chia-Ping Tsai <chia7712@gmail.com>, Manikumar Reddy <manikumar.reddy@gmail.com>

Closes #8481 from sebwills/patch-1

bin/kafka-run-class.sh

@@ -295,7 +295,7 @@ if [ "x$GC_LOG_ENABLED" = "xtrue" ]; then
   # 10 -> java version "10" 2018-03-20
   # 10.0.1 -> java version "10.0.1" 2018-04-17
   # We need to match to the end of the line to prevent sed from printing the characters that do not match
-  JAVA_MAJOR_VERSION=$($JAVA -version 2>&1 | sed -E -n 's/.* version "([0-9]*).*$/\1/p')
+  JAVA_MAJOR_VERSION=$("$JAVA" -version 2>&1 | sed -E -n 's/.* version "([0-9]*).*$/\1/p')
   if [[ "$JAVA_MAJOR_VERSION" -ge "9" ]] ; then
     KAFKA_GC_LOG_OPTS="-Xlog:gc*:file=$LOG_DIR/$GC_LOG_FILE_NAME:time,tags:filecount=10,filesize=102400"
   else
@@ -313,7 +313,7 @@ CLASSPATH=${CLASSPATH#:}
 
 # Launch mode
 if [ "x$DAEMON_MODE" = "xtrue" ]; then
-  nohup $JAVA $KAFKA_HEAP_OPTS $KAFKA_JVM_PERFORMANCE_OPTS $KAFKA_GC_LOG_OPTS $KAFKA_JMX_OPTS $KAFKA_LOG4J_OPTS -cp "$CLASSPATH" $KAFKA_OPTS "$@" > "$CONSOLE_OUTPUT_FILE" 2>&1 < /dev/null &
+  nohup "$JAVA" $KAFKA_HEAP_OPTS $KAFKA_JVM_PERFORMANCE_OPTS $KAFKA_GC_LOG_OPTS $KAFKA_JMX_OPTS $KAFKA_LOG4J_OPTS -cp "$CLASSPATH" $KAFKA_OPTS "$@" > "$CONSOLE_OUTPUT_FILE" 2>&1 < /dev/null &
 else
-  exec $JAVA $KAFKA_HEAP_OPTS $KAFKA_JVM_PERFORMANCE_OPTS $KAFKA_GC_LOG_OPTS $KAFKA_JMX_OPTS $KAFKA_LOG4J_OPTS -cp "$CLASSPATH" $KAFKA_OPTS "$@"
+  exec "$JAVA" $KAFKA_HEAP_OPTS $KAFKA_JVM_PERFORMANCE_OPTS $KAFKA_GC_LOG_OPTS $KAFKA_JMX_OPTS $KAFKA_LOG4J_OPTS -cp "$CLASSPATH" $KAFKA_OPTS "$@"
 fi