RFR(S): 8157438 - JVMCI: MaterializeVirtualObjectTest fails w/ "CASE: invalidate=true: has no virtual object before"

[Dmitrij Pochepko]

Hi,

please review fix for 8157438 - JVMCI: MaterializeVirtualObjectTest 
fails w/ "CASE: invalidate=true: has no virtual object before"
The reason was a test bug: compile threshold was calculated, but not 
correctly used, so, incorrect value was used in case of non-tiered mode.

webrev: http://cr.openjdk.java.net/~dpochepk/8157438/webrev.01/
CR: https://bugs.openjdk.java.net/browse/JDK-8157438

I've tested this fix on linux_x64

Thanks,
Dmitrij