RFR(XXS) 8230385 [cds] No message is logged when shared image cannot be used due to mismatched configuration

[Ioi Lam]

https://bugs.openjdk.java.net/browse/JDK-8230385
http://cr.openjdk.java.net/~iklam/jdk14/8230385-log-when-cds-is-disabled.v01/

Please review this one-liner addition that prints a log message when CDS 
cannot be used. Output:

$ java -XX:-UseCompressedOops -Xlog:cds -version
[0.001s][info][cds] Unable to use shared archive: UseCompressedOops and 
UseCompressedClassPointers must be on for UseSharedSpaces.
java version "14-internal" 2020-03-17
Java(TM) SE Runtime Environment (fastdebug build 
14-internal+0-adhoc.iklam.open)
Java HotSpot(TM) 64-Bit Server VM (fastdebug build 
14-internal+0-adhoc.iklam.open, mixed mode)

Thanks
- Ioi