[10] RFR (XS): 8185624: G1HeapVerifier's VerifyRootsClosure prints important information on info log level

[Muthusamy Chinnathambi]

Hi,

Please review this trivial change for the fix of bug 'JDK-8185624 G1HeapVerifier's VerifyRootsClosure prints important information on info log level'

Summary:
VerifyRootsClosure logs information about the broken oop on the gc+verify=error tag/level combination. But it does so on the "info" log level. This change is to get this information on the error log level.

jdk10 bug: https://bugs.openjdk.java.net/browse/JDK-8185624
webrev link: http://cr.openjdk.java.net/~shshahma/Muthu/8185624/webrev.00/

Testing: jprt default and hotspot testsets

Regards,
Muthusamy C