treat SIGFPE like SIGSEGV and SIGBUS since could arise in client library

_From [derek.br...@gmail.com](https://code.google.com/u/117968039472581148324/) on September 25, 2009 12:54:28_

a client library could use integer or floating-point division and raise
SIGFPE, which should then be treated as a client fault. today we hit the
abort in record_pending_signal on a synchronous signal not in the code
cache but better to treat as a client fault earlier.

_Original issue: http://code.google.com/p/dynamorio/issues/detail?id=208_