RFR: 8216157: Enable inlining of java_lang_Class::is_primitive

[Claes Redestad]

Hi,

moving Class::is_primitive to javaClasses.inline.hpp turns out to be a
micro-optimization on a number of operations, such as Array.newInstance
(until the C2 intrinsic kicks in).

As the method is quite trivial inlining seem to happen everywhere and
still end up shrinking the VM size by a few bytes (linux-x64).

Bug:    https://bugs.openjdk.java.net/browse/JDK-8216157
Webrev: http://cr.openjdk.java.net/~redestad/8216157/open.00/

Testing: tier1-3 in-flight

/Claes