Generated QIR is not valid when doing multi-qubit measurement inside a repeat statement

[cesarzc]

Describe the bug

Generated QIR is not valid when doing multi-qubit measurement inside a repeat statement.

To Reproduce

Steps to reproduce the behavior:

1. Compiling a Q# project with the following code and setting the projects <QirGeneration>true</QirGeneration> property generates QIR that fails verification:

   namespace Issue {
   open Microsoft.Quantum.Intrinsic;
   open Microsoft.Quantum.Measurement;
   
   @EntryPoint()
   operation Main() : Int {
       use register = Qubit[5];
       mutable count = 0;
       repeat {
           let results = MultiM(register);
           if (results[0] == Zero)
           {
               set count += 1;
           }
   
       } until (count < 5); 
   
       return count;
   }
   }

2. After the QIR code is generated, use the llvm-as command on to generate bitcode: llvm-as-13 qir/Program.ll -o qir/Program.bc

3. The following error is produced:

   llvm-as-13: assembly parsed, but does not verify as correct!
   Instruction does not dominate all uses!
   %10 = call i64 @__quantum__rt__array_get_size_1d(%Array* %results)
   %9 = sub i64 %10, 1