The fix for JDK-8249158 removes the call for JvmtiExport::post_vm_start() from Threads::create_vm():

https://hg.openjdk.java.net/jdk8u/jdk8u-dev/hotspot/rev/85e682d8ab91#l11.24

This fix is supposed to be a backout of the fix for JDK-8233197, so this removal seems to be done by a mistake, because the call for JvmtiExport::post_vm_start() was present there prior to the fix for JDK-8233197:
https://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/rev/26d1803768c7#l11.21

This change causes failures in the vmTestbase suite, which is not yet included into jdk8u though. Probably some jvmti usecases could be affected also.

Suggested fix:
diff --git a/src/share/vm/runtime/thread.cpp b/src/share/vm/runtime/thread.cpp
--- a/src/share/vm/runtime/thread.cpp
+++ b/src/share/vm/runtime/thread.cpp
@@ -3496,6 +3496,7 @@
   JvmtiExport::enter_start_phase();
 
   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
+ JvmtiExport::post_vm_start();
 
   {
     TraceTime timer("Initialize java.lang classes", TraceStartupTime);