### What changes were proposed in this pull request?
This PR refactors test code in order to improve the debugability of `SparkSubmitSuite`.
The `sql/hive` module contains a `SparkSubmitTestUtils` helper class which launches `spark-submit` and captures its output in order to display better error messages when tests fail. This helper is currently used by `HiveSparkSubmitSuite` and `HiveExternalCatalogVersionsSuite`, but isn't used by `SparkSubmitSuite`.
In this PR, I moved `SparkSubmitTestUtils` and `ProcessTestUtils` into the `core` module and updated `SparkSubmitSuite`, `BufferHolderSparkSubmitSuite`, and `WholestageCodegenSparkSubmitSuite` to use the relocated helper classes. This required me to change `SparkSubmitTestUtils` to make its timeouts configurable and to generalize its method for locating the `spark-submit` binary.
### Why are the changes needed?
Previously, `SparkSubmitSuite` tests would fail with messages like:
```
[info] - launch simple application with spark-submit *** FAILED *** (1 second, 832 milliseconds)
[info] Process returned with exit code 101. See the log4j logs for more detail. (SparkSubmitSuite.scala:1551)
[info] org.scalatest.exceptions.TestFailedException:
[info] at org.scalatest.Assertions.newAssertionFailedException(Assertions.scala:472)
```
which require the Spark developer to hunt in log4j logs in order to view the logs from the failed `spark-submit` command.
After this change, those tests will fail with detailed error messages that include the text of failed command plus timestamped logs captured from the failed proces:
```
[info] - launch simple application with spark-submit *** FAILED *** (2 seconds, 800 milliseconds)
[info] spark-submit returned with exit code 101.
[info] Command line: '/Users/joshrosen/oss-spark/bin/spark-submit' '--class' 'invalidClassName' '--name' 'testApp' '--master' 'local' '--conf' 'spark.ui.enabled=false' '--conf' 'spark.master.rest.enabled=false' 'file:/Users/joshrosen/oss-spark/target/tmp/spark-0a8a0c93-3aaf-435d-9cf3-b97abd318d91/testJar-1631768004882.jar'
[info]
[info] 2021-09-15 21:53:26.041 - stderr> SLF4J: Class path contains multiple SLF4J bindings.
[info] 2021-09-15 21:53:26.042 - stderr> SLF4J: Found binding in [jar:file:/Users/joshrosen/oss-spark/assembly/target/scala-2.12/jars/slf4j-log4j12-1.7.30.jar!/org/slf4j/impl/StaticLoggerBinder.class]
[info] 2021-09-15 21:53:26.042 - stderr> SLF4J: Found binding in [jar:file:/Users/joshrosen/.m2/repository/org/slf4j/slf4j-log4j12/1.7.30/slf4j-log4j12-1.7.30.jar!/org/slf4j/impl/StaticLoggerBinder.class]
[info] 2021-09-15 21:53:26.042 - stderr> SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
[info] 2021-09-15 21:53:26.042 - stderr> SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
[info] 2021-09-15 21:53:26.619 - stderr> Error: Failed to load class invalidClassName. (SparkSubmitTestUtils.scala:97)
[info] org.scalatest.exceptions.TestFailedException:
[info] at org.scalatest.Assertions.newAssertionFailedException(Assertions.scala:472)
```
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
I manually ran the affected test suites.
Closes#34013 from JoshRosen/SPARK-36774-move-SparkSubmitTestUtils-to-core.
Authored-by: Josh Rosen <joshrosen@databricks.com>
Signed-off-by: Josh Rosen <joshrosen@databricks.com>
(cherry picked from commit 3ae6e6775b)
Signed-off-by: Josh Rosen <joshrosen@databricks.com>
3502fda783