[LLVM16] [LITS] Remove invalid null check in AliasAnalysis LLVM wrapper

Porting IGC code to LLVM16

This NULL check is not valid because LLVM's AliasAnalysis originally performs such a call on 16:

```
AliasResult AAResults::alias(const MemoryLocation &LocA,
                             const MemoryLocation &LocB) {
  SimpleAAQueryInfo AAQIP(*this);
  return alias(LocA, LocB, AAQIP, nullptr);
}
```

where nullPtr = const Instruction *CtxI

FYI: On LLVM 14 it is just

```
AliasResult AAResults::alias(const MemoryLocation &LocA,
                             const MemoryLocation &LocB) {
  SimpleAAQueryInfo AAQIP;
  return alias(LocA, LocB, AAQIP);
}
```

Fixes:
AddressSpaceAliasAnalysis/rt-basic.ll

Author: bokrzesi

IGC/WrapperLLVM/include/llvmWrapper/Analysis/AliasAnalysis.h

@@ -42,7 +42,6 @@ namespace IGCLLVM
                         #endif
     ) {
 #if LLVM_VERSION_MAJOR >= 16
-      IGC_ASSERT_MESSAGE(CtxI != nullptr, "CtxI is null");
       return llvm::AAResultBase::alias(LocA, LocB, AAQI, CtxI);
 #else
       return llvm::AAResultBase<T>::alias(LocA, LocB, AAQI);