[sanitizer] Fix a crash in SizeClassAllocator32 with an out-of-range pointer

This happens on a 64-bit platform that uses SizeClassAllocator32 (e.g. ASan on AArch64). When querying a large invalid pointer, `__sanitizer_get_allocated_size(0xdeadbeefdeadbeef)`, an assertion will fail.  This patch changes PointerIsMine to return false if the pointer is outside of [kSpaceBeg, kSpaceBeg + kSpaceSize).

Differential Revision: http://reviews.llvm.org/D15008

llvm-svn: 268243