RFR 8028275: Metaspace ShrinkGrowTest causes fatal error if run with JFR

[Coleen Phillimore]

Summary: Clean up initialization from Threads::create_vm() so that 
exceptions cause vm_exit_during_initialization without an exception mark.

My attempt at cleaning up initialization code paths that can throw an 
exception.  I only cleaned up the code in Threads::create_vm(). There 
are other places where EXCEPTION_MARK can occur after 
Universe::is_fully_initialized() and before is_initialization_complete() 
deeply embedded in the code.   But I did some refactoring.

open webrev at http://cr.openjdk.java.net/~coleenp/8028275/
bug link https://bugs.openjdk.java.net/browse/JDK-8028275

Tested with nsk.quick.testlist and with the hotspot jtreg tests, and 
some custom code to test exception paths.

Thanks,
Coleen