throw a C++ exception when replaced non-nothrow operator new fails to allocate memory

_From [bruen...@google.com](https://code.google.com/u/109494838902877177630/) on August 06, 2012 14:32:35_

split from issue #882 non-nothrow new needs to throw an exception! for now we'll just exit the process. it seems that valgrind has been doing that for years and it has been sufficient.

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=957_