RFR(M/L) : 8209611 : use C++ compiler for hotspot tests

[Igor Ignatev]

Because we would like to clean them up, which includes , but not limited to, removing JNI_ENV* and the like macros, other instances of ifndef __cplusplus. 

— Igor

> On Aug 20, 2018, at 11:39 PM, David Holmes <david.holmes at oracle.com> wrote:
> 
> Okay, but why do we need to change any of these existing tests to be compiled as C++?