RFR(XS): JDK-8040018 Remove bad assert in ClassFileParser.cpp

[harold seigel]

Hi,

Please review this small change to fix bug JDK-8040018 for JDK-9. The 
fix removes the assert because it can be triggered by a class file 
containing an incorrect attribute_length value for the BoostrapMethods 
attribute, not just by a JVM inconsistency. Removing the assert lets the 
following guarantee_property() call catch the problem and throw a 
java.lang.ClassFormatError exception.

The fix was tested with JPRT, JCK lang, JCK vm, hotspot jtreg, and nsk 
quick tests.  The new test was tested on Linux and Windows.

Open webrev at: http://cr.openjdk.java.net/~hseigel/bug_8040018/ 
<http://cr.openjdk.java.net/%7Ehseigel/bug_8040018/>
Bug: https://bugs.openjdk.java.net/browse/JDK-8040018

Thanks! Harold