[Passes] Enable the relative lookup table converter pass on aarch64

After d5c5cf5ce8, it should work fine
for aarch64 on COFF too. (It was disabled when the patch was
(re)applied in e96df3e531, pending
that fix.)

llvm/include/llvm/CodeGen/BasicTTIImpl.h

@@ -397,11 +397,6 @@ public:
     if (!TargetTriple.isArch64Bit())
       return false;
 
-    // TODO: Triggers an issue in aarch64, so temporarily disable it.
-    // See https://reviews.llvm.org/D99572 for more information.
-    if (TargetTriple.getArch() == Triple::aarch64)
-      return false;
-
     return true;
   }