Convert jvmtiThread.c to jvmtiThread.cpp

[babsingh]

This will simplify future changes for virtual thread support.

[babsingh]

jenkins test sanity plinux,win jdk8,jdk21

[babsingh]

jenkins test extended.openjdk zlinux jdk21

[babsingh]

Failures seen in the builds are unrelated to the PR:

• [KNOWN] JDK21 serviceability/jvmti/vthread/FollowReferences/VThreadStackRefTest.java ERROR class VThreadStackRefTest$VThreadMountedJNIReferenced: ref count = 1 (expected 1), thread id = 0 (expected 27) #18426
• [KNOWN] [win_x86-64_cmprssptrs] SE80_GIT cmdLineTest_J9test_elapsedTime_0 FAILED: testElapsedTime() wait 100ms elapsedNanoTimeInMillis (96ms) should NOT be less than minElapsedNanoTimeInMillis (100ms) #18456

https://openj9-jenkins.osuosl.org/job/Test_openjdk21_j9_extended.openjdk_s390x_linux_Personal/6/consoleFull

A timeout in GetThreadStateTest is seen, which is seen for the first time. Locally, this failure occurs intermittently. This PR doesn't change any functionality so it is not cause for this failure. I will open an issue to document the intermittent GetThreadStateTest failure.

[babsingh]

@gacholio Requesting your review. Taking an approach similar to #18413 w.r.t. the cpp conversion. These changes don't impact functionality; they should only break compilation in the worst-case.

[gacholio]

I personally prefer (type*) to (type *) but I won't insist. What is the reason for this change?

[gacholio]

Almost every test suite failed - this is not a sensible situation to be in.

[gacholio]

Given the compile successes, this is ready for merge.

[babsingh]

I personally prefer (type*) to (type *) but I won't insist.

(type *) is used to be consistent with the existing format in the file.

What is the reason for this change?

To support a follow up change in https://github.com/babsingh/openj9/commits/main3 (WIP).

[tajila]

@babsingh you may need to triple deliver to 0.42 and 0.43

[babsingh]

Backports:

• [0.42] Virtual Thread Support #18494
• [0.43] Virtual Thread Support #18495