RFR(S): 8087183: Fix call to inline function is_oop in header debugInfo.hpp.

[Lindenmaier, Goetz]

Hi,

in debugInfo.hpp is_oop() is called.  This is an inline function defined in oop.inline.hpp.
As oop.inline.hpp is not included in debugInfo.hpp, and it should not be included there,
this leads to compilation failures in the fastdebug build on aix.

To fix this, I just move the function calling is_oop to debugInfo.cpp.  In that file also the
only call to that function is located, so that it still can be inlined.

Please review this change.  I please need a sponsor.
http://cr.openjdk.java.net/~goetz/webrevs/8087183-is_oop/webrev-01/

Best regards,
  Goetz.