(10) RFR (actually S) 8169881: Remove implicit Handle conversions oop->Handle

[Coleen Phillimore]

Summary: Pass THREAD to Handle as argument instead of implicit 
Thread::current() call.

It's a very small change to a number of files.  Notably the new JVMCI 
files have a lot of implicit conversions from oop to handle. I want to 
get this change in early for jdk10 to stop this usage.  I also added a 
few HandleMarks where I found that the HandlesArea was growing large.

See bug for more on the motivation of this change.

open webrev at http://cr.openjdk.java.net/~coleenp/8169881.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8169881

Tested by running all hotspot jtreg tests with -XX:+CheckUnhandledOops.  
There weren't any unhandled oops amazingly.

Thanks,
Coleen