[ASan] Move the shadow range on 32-bit iOS (and iOS Simulator)
to 0x40000000-0x60000000 to avoid address space clash with system libraries.
The solution has been proposed by tahabekireren@gmail.com in https://code.google.com/p/address-sanitizer/issues/detail?id=210
This is also known to fix some Chromium iOS tests.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207002 91177308-0d34-0410-b5e6-96231b3b80d8