hwasan: Fix relocation errors by adjusting NewGV alias address calculation

We don't want to apply `PointerTagShift` to the alias address of `NewGV`
that replaces the `GV` we are instrumenting, because that makes the
address huge and results in relocation errors such as:

    hwaddress.7rcbfp3g-cgu.0:(.text.main+0x7c): \
        relocation truncated to fit: R_AARCH64_ADR_PREL_PG_HI21 against `.data.rel.ro..L.hwasan'

unless optimizations happens get rid of the faulty calculation.

Author: Enselic

llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp

@@ -1763,9 +1763,7 @@ void HWAddressSanitizer::instrumentGlobal(GlobalVariable *GV, uint8_t Tag) {
   }
 
   Constant *Aliasee = ConstantExpr::getIntToPtr(
-      ConstantExpr::getAdd(
-          ConstantExpr::getPtrToInt(NewGV, Int64Ty),
-          ConstantInt::get(Int64Ty, uint64_t(Tag) << PointerTagShift)),
+      ConstantExpr::getPtrToInt(NewGV, Int64Ty),
       GV->getType());
   auto *Alias = GlobalAlias::create(GV->getValueType(), GV->getAddressSpace(),
                                     GV->getLinkage(), "", Aliasee, &M);