[SPARK-32996][Web-UI][FollowUP] Move ExecutorSummarySuite to proper path

[shrutig]

What changes were proposed in this pull request?

This change updates the test file location in #29872 to proper path.

Why are the changes needed?

ExecutorSummarySuite.scala should be in core/src/test/scala instead of core/src/test/java.

Does this PR introduce any user-facing change?

No

How was this patch tested?

Unit tests

[viirya]

ok to test

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/33932/

[viirya]

look good pending test.

[SparkQA]

Kubernetes integration test status failure
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/33932/

[SparkQA]

Test build #129319 has finished for PR 29926 at commit 5edeb0f.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[viirya]

Thanks! Merging to master.

[SparkQA]

Test build #129318 has finished for PR 29926 at commit 5edeb0f.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.