[SPARK-8731] Beeline doesn't work with -e option when started in background

### What changes were proposed in this pull request?
Append jline option "-Djline.terminal=jline.UnsupportedTerminal" to  enable the Beeline process to run in background.

### Why are the changes needed?
Currently, if we execute spark Beeline in background, the Beeline process stops immediately.
<img width="1350" alt="image" src="https://user-images.githubusercontent.com/88070094/194742935-8235b1ba-386e-4470-b182-873ef185e19f.png">

### Does this PR introduce _any_ user-facing change?
User will be able to execute Spark Beeline in background.

### How was this patch tested?

1. Start Spark ThriftServer
2. Execute command `./bin/beeline -u "jdbc:hive2://localhost:10000" -e "select 1;" &`
3. Verify Beeline process output in console:
<img width="1407" alt="image" src="https://user-images.githubusercontent.com/88070094/194743153-ff3f1d19-ac23-443b-97a6-f024719008cd.png">

### Note

Beeline works fine on Windows when backgrounded:
![image](https://user-images.githubusercontent.com/88070094/194743797-7dc4fc21-dec6-4056-8b13-21fc96f1476e.png)

Closes apache#38172 from zhouyifan279/SPARK-8731.

Authored-by: zhouyifan279 <[email protected]>
Signed-off-by: Kent Yao <[email protected]>

Author: zhouyifan279

bin/load-spark-env.sh

@@ -63,3 +63,8 @@ if [ -z "$SPARK_SCALA_VERSION" ]; then
     export SPARK_SCALA_VERSION=${SCALA_VERSION_2}
   fi
 fi
+
+# Append jline option to enable the Beeline process to run in background.
+if [[ ( ! $(ps -o stat= -p $$) =~ "+" ) && ! ( -p /dev/stdin ) ]]; then
+  export SPARK_BEELINE_OPTS="$SPARK_BEELINE_OPTS -Djline.terminal=jline.UnsupportedTerminal"
+fi