[SPARK-3534] Fix expansion of testing arguments to sbt

Testing arguments to `sbt` need to be passed as an array, not a single, long string.

Fixes a bug introduced in apache#2420.

Author: Nicholas Chammas <nicholas.chammas@gmail.com>

Closes apache#2437 from nchammas/selective-testing and squashes the following commits:

a9f9c1c [Nicholas Chammas] fix printing of sbt test arguments
cf57cbf [Nicholas Chammas] fix sbt test arguments
e33b978 [Nicholas Chammas] Merge pull request #2 from apache/master
0b47ca4 [Nicholas Chammas] Merge branch 'master' of github.com:nchammas/spark
8051486 [Nicholas Chammas] Merge pull request #1 from apache/master
03180a4 [Nicholas Chammas] Merge branch 'master' of github.com:nchammas/spark
d4c5f43 [Nicholas Chammas] Merge pull request #6 from apache/master

dev/run-tests

@@ -141,25 +141,28 @@ echo "========================================================================="
 
 {
   # If the Spark SQL tests are enabled, run the tests with the Hive profiles enabled.
+  # This must be a single argument, as it is.
   if [ -n "$_RUN_SQL_TESTS" ]; then
     SBT_MAVEN_PROFILES_ARGS="$SBT_MAVEN_PROFILES_ARGS -Phive"
   fi
 
   if [ -n "$_SQL_TESTS_ONLY" ]; then
-    SBT_MAVEN_TEST_ARGS="catalyst/test sql/test hive/test"
+    # This must be an array of individual arguments. Otherwise, having one long string
+    #+ will be interpreted as a single test, which doesn't work.
+    SBT_MAVEN_TEST_ARGS=("catalyst/test" "sql/test" "hive/test")
   else
-    SBT_MAVEN_TEST_ARGS="test"
+    SBT_MAVEN_TEST_ARGS=("test")
   fi
 
-  echo "[info] Running Spark tests with these arguments: $SBT_MAVEN_PROFILES_ARGS $SBT_MAVEN_TEST_ARGS"
+  echo "[info] Running Spark tests with these arguments: $SBT_MAVEN_PROFILES_ARGS ${SBT_MAVEN_TEST_ARGS[@]}"
 
   # NOTE: echo "q" is needed because sbt on encountering a build file with failure
   #+ (either resolution or compilation) prompts the user for input either q, r, etc
   #+ to quit or retry. This echo is there to make it not block.
   # QUESTION: Why doesn't 'yes "q"' work?
   # QUESTION: Why doesn't 'grep -v -e "^\[info\] Resolving"' work?
   echo -e "q\n" \
-    | sbt/sbt "$SBT_MAVEN_PROFILES_ARGS" "$SBT_MAVEN_TEST_ARGS" \
+    | sbt/sbt "$SBT_MAVEN_PROFILES_ARGS" "${SBT_MAVEN_TEST_ARGS[@]}" \
     | grep -v -e "info.*Resolving" -e "warn.*Merging" -e "info.*Including"
 }