[mlir][VectorOps] Support string literals in vector.print (#68695)

Printing strings within integration tests is currently quite annoyingly
verbose, and can't be tucked into shared helpers as the types depend on
the length of the string:

```
llvm.mlir.global internal constant @hello_world("Hello, World!\0")

func.func @entry() {
  %0 = llvm.mlir.addressof @hello_world : !llvm.ptr<array<14 x i8>>
  %1 = llvm.mlir.constant(0 : index) : i64
  %2 = llvm.getelementptr %0[%1, %1]
    : (!llvm.ptr<array<14 x i8>>, i64, i64) -> !llvm.ptr<i8>
  llvm.call @printCString(%2) : (!llvm.ptr<i8>) -> ()
  return
}
```

So this patch adds a simple extension to `vector.print` to simplify
this:
```
func.func @entry() {
   // Print a vector of characters ;)
   vector.print str "Hello, World!"
   return
}
```

Most of the logic for this is now shared with `cf.assert` which already
does something similar.

Depends on #68694

mlir/lib/Conversion/VectorToLLVM/ConvertVectorToLLVM.cpp

@@ -9,6 +9,7 @@
 #include "mlir/Conversion/VectorToLLVM/ConvertVectorToLLVM.h"
 
 #include "mlir/Conversion/ArithCommon/AttrToLLVMConverter.h"
+#include "mlir/Conversion/LLVMCommon/PrintCallHelper.h"
 #include "mlir/Conversion/LLVMCommon/TypeConverter.h"
 #include "mlir/Conversion/LLVMCommon/VectorPattern.h"
 #include "mlir/Dialect/Arith/IR/Arith.h"
@@ -1548,7 +1549,10 @@ public:
     }
 
     auto punct = printOp.getPunctuation();
-    if (punct != PrintPunctuation::NoPunctuation) {
+    if (auto stringLiteral = printOp.getStringLiteral()) {
+      LLVM::createPrintStrCall(rewriter, loc, parent, "vector_print_str",
+                               *stringLiteral, *getTypeConverter());
+    } else if (punct != PrintPunctuation::NoPunctuation) {
       emitCall(rewriter, printOp->getLoc(), [&] {
         switch (punct) {
         case PrintPunctuation::Close: