Add bound violation handling for Intel(R) Memory Protection Extensions (Intel(R) MPX)

Summary:
This patch adds support for handling the SIGSEGV signal with 'si_code ==
SEGV_BNDERR', which is thrown when a bound violation is caught by the
Intel(R) MPX technology.

Differential Revision: https://reviews.llvm.org/D25329

llvm-svn: 283474