RFR(XXS): 8019382 : PPC64: Fix bytecodeInterpreter to compile with '-Wunused-value'

[Volker Simonis]

Hi,

this is a patch from the PowerPC/AIX porting project but it only
changes shared code and it fixes a build problem in the C++
interpreter which also affects the Zero-Port so I would strongly
recommend to push it right into the hotspot repository.

The problem is related to "8014431 : cleanup warnings indicated by the
-Wunused-value compiler option on linux" which added the
"-Wunused-value" option to the Linux build but did not clean up the
code in the c++ interpreter. This lead to several warnings which are
now treated as errors when compiling bytecodeInterpreter.cpp.

The fix is easy - just cast the offending expressions to void:

http://cr.openjdk.java.net/~simonis/webrevs/8019382/

Thank you and best regards,
Volker