RFR: 7468: Fix jdp test coverage

[Marcus Hirt]

On Fri, 3 Dec 2021 19:52:34 GMT, Alex Macdonald <aptmac at openjdk.org> wrote:

> This PR addresses JMC-7468 [[0]](https://bugs.openjdk.java.net/browse/JMC-7468), in which the jdp test coverage is not added to the core coverage report.
> 
> The one-liner fix here is to make sure the argLine used by Jacoco is not overwritten by the surefire-plugin in the jdp.test pom.
> 
> Before (0%):
> ![2021-12-03-141742_1091x251_scrot](https://user-images.githubusercontent.com/10425301/144663611-4424aae8-947c-4006-a26d-335ab325bfef.png)
> 
> After (60%):
> ![2021-12-03-144244_1092x258_scrot](https://user-images.githubusercontent.com/10425301/144663625-5fc72bc8-c243-4f86-b00a-6f9d6a8cc3e7.png)
> 
> [0] https://bugs.openjdk.java.net/browse/JMC-7468

Marked as reviewed by hirt (Lead).

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PR: https://git.openjdk.java.net/jmc/pull/340