RFR 8187436: -Xbootclasspath/a causes sanity check assertion with exploded build

[harold seigel]

Hi,

Please review this JDK-10 change to fix an assertion involving 
ClassLoader::_num_entries.  The assertion gets triggered when running 
the exploded build.  ClassLoader::_num_entries is only used by CDS, 
which is not supported for exploded builds.  So, assertions involving 
_num_entries should check for a normal build before doing their check 
involving _num_entries.

Note that a new RFE will be filed shortly requesting a re-design of the 
confusing boot classpath entries code as requested in one of the 
comments in this JBS bug.

Open webrev: 
http://cr.openjdk.java.net/~hseigel/bug_8187436/webrev/index.html

JBS Bug: https://bugs.openjdk.java.net/browse/JDK-8187436

The change was tested with the JCK Lang and VM tests, the JTreg hotspot, 
java/io, java/lang, java/util, and other tests.  The test were run with 
both the normal and exploded builds.

Thanks, Harold