[KYUUBI-7659][INFRA] Restore code coverage by not overriding the test argLine

[zhang-arvin]

What changes were proposed in this pull request?

-Pcodecov hasn't produced any coverage since 1.8.0 because both maven-surefire-plugin and scalatest-maven-plugin override their argLine with ${extraJavaTestArgs}, which drops the JaCoCo agent that jacoco:prepare-agent publishes to the ${argLine} property.

This PR moves the JDK --add-opens options into the argLine property itself (referencing extraJavaTestArgs) and removes the argLine overrides from both plugin configs. This allows jacoco:prepare-agent to prepend its agent to the property's existing value.

How was this patch tested?

Manual verification:

build/mvn test -Pcodecov -pl kyuubi-util-scala

Should produce target/jacoco.exec and a coverage report.

Closes #7659

[wangzhigang1999]

@zhang-arvin,

I am closing [PR 7680](#7680) and [PR 7681](#7681) because the proposed fixes are not suitable in their current form.

[PR 7682](#7682) duplicates the approved [PR 7669](#7669), and [PR 7683](#7683) duplicates the active [PR 7661](#7661).

Please check for existing work and coordinate with other contributors before opening a PR. Also follow the PR template and include test results.