RFR: 8291: JVM PID is shown as N/A however the value is present in JFR

[Suchita Chaturvedi]

This is a regression found during internal testing.

PID issue was fixed in [JMC-7506](https://bugs.openjdk.org/browse/JMC-7506). The pid in system process was coming as string and the pid in VM information was coming as long. Hence,  to maintain the uniformity both the considered as string and changes are done to convert JVM PID from IQuantity/Long to String.

[JMC-8244](https://bugs.openjdk.org/browse/JMC-8244) Turned off all the scientific notations for long attributes. Hence, JVM_PID is no longer IQuantity/Long. Its a Raw number.

Both these fixes overlapped and PID on JVM Internals screen started showing as N/A.

![image](https://github.com/user-attachments/assets/25e9e370-cd53-44a6-a833-b8b24639d644)

Though the value of PID is present.
![image](https://github.com/user-attachments/assets/dbf1b76a-4567-408a-9407-54e54a5b294c)


After handling the datatypes properly, the issue has been fixed:
<img width="335" alt="image" src="https://github.com/user-attachments/assets/24154a14-19c0-4594-b40e-74a198835a17">

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Commit messages:
 - 8291: JVM PID is shown as N/A however the value is present in JFR

Changes: https://git.openjdk.org/jmc/pull/608/files
  Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=608&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-8291
  Stats: 4 lines in 2 files changed: 0 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jmc/pull/608.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/608/head:pull/608

PR: https://git.openjdk.org/jmc/pull/608