[sanitizer] Move termination functions in their own file

Summary:
As suggested by kcc@ in http://reviews.llvm.org/D20084#441418, move the CheckFailed and Die functions, and their associated callback functionalities in their own separate file.
I expended the build rules to include a new rule that would not include those termination functions, so that another project can define their own.
The tests check-{a,t,m,ub,l,e,df}san are all passing.

Reviewers: llvm-commits, kcc

Subscribers: kubabrecka

Differential Revision: http://reviews.llvm.org/D20742

llvm-svn: 271055