[asan] Don't assert that a target is within 2GB on 32-bit Windows

Summary:
In a 32-bit address space, PC-relative jump targets are wrapped, so a
direct branch at 0x90000001 can reach address 0x10000000 with a
displacement of 0x7FFFFFFFF. This can happen in applications, such as
Chrome, that are linked with /LARGEADDRESSAWARE.

Reviewers: etienneb

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D26650

llvm-svn: 286997