[9] RFR(S): 8041992: Fix of JDK-8034775 neglects to account for non-JIT VMs

[Albert]

Hi,

could I get reviews for the following bug?
The proposed fix for this bug is provided by Severin (see cc).

Bug:
https://bugs.openjdk.java.net/browse/JDK-8041992

Problem:
JDK-8034775 restricts the number of compiler threads to be at least 1. 
This restriction does not make sense for a non-JIT JVM (zero).

Solution:
Allow 0 compiler threads if no JIT is used.

Testing:
Failing test case

Webrev:
http://cr.openjdk.java.net/~anoll/8041992/webrev.00/

Many thanks,
Albert