[ASan] Refactoring: nuke the redundant function declarations in asan_intercepted_functions.h
that had been used on OS X only.
The INTERCEPTOR() macro on OS X is now responsible for declaring the wrapped function, the wrapper and the
pair of pointers to them in __DATA,__interposition section. Thus adding an interceptor requires editing a single file now.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@175740 91177308-0d34-0410-b5e6-96231b3b80d8