RFR(XS): 8142387: Various JVMCI tests fail on unexpected exception

[Roland Schatz]

Hi,

Please review this small fix for the compiler/jvmci/errors tests.

These tests check that invalid input data is handled properly in the C++ 
part of JVMCI, instead of crashing the vm.
Some of the intentionally broken input data fails assertions in the Java 
part of the JVMCI. We need to run these tests with assertions disabled, 
so we can get the broken data through to the C++ code.

One assertion was unrelated to the intentionally broken input data. I 
fixed that one.

JIRA:
https://bugs.openjdk.java.net/browse/JDK-8142387

Webrev:
http://cr.openjdk.java.net/~rschatz/JDK-8142387/webrev.00/

Thanks,
Roland