[8u] RFR 8249158: THREAD_START and THREAD_END event posted in primordial phase

[Jaroslav Bachorík]

This patch is backing out the backport of JDK-8233197. The backport
changed slightly the init order and thus broke the expected behavior
of the JVMTI VMStart routine (more information in JIRA ticket).

Since the original fix (JDK-8233197) is fixing an issue which can not
be hit in JDK 8 due to different implementation of the VM init phases
it makes sense to back out the backport and restore the original JVMTI
behavior.

JIRA : https://bugs.openjdk.java.net/browse/JDK-8249158
CR    : http://cr.openjdk.java.net/~jbachorik/8249158

The backout is fairly straightforward. When applied all jdk/jfr and
hotspot/runtime tests are passing.

Cheers,

-JB-