[llvm] [SandboxIR] Add missing VectorType functions (PR #107650)

[via llvm-commits]

================
@@ -268,16 +268,50 @@ define void @foo({i32, i8} %v0) {
 
 TEST_F(SandboxTypeTest, VectorType) {
   parseIR(C, R"IR(
-define void @foo(<2 x i8> %v0) {
+define void @foo(<4 x i16> %vi0, <4 x float> %vf1, i8 %i0) {
   ret void
 }
 )IR");
   llvm::Function *LLVMF = &*M->getFunction("foo");
   sandboxir::Context Ctx(C);
   auto *F = Ctx.createFunction(LLVMF);
-  // Check classof(), creation.
-  [[maybe_unused]] auto *VecTy =
-      cast<sandboxir::VectorType>(F->getArg(0)->getType());
+  // Check classof(), creation, accessors
+  auto *VecTy = cast<sandboxir::VectorType>(F->getArg(0)->getType());
+  EXPECT_TRUE(VecTy->getElementType()->isIntegerTy(16));
+  EXPECT_EQ(VecTy->getElementCount(), ElementCount::getFixed(4));
+
+  auto *FVecTy = cast<sandboxir::VectorType>(F->getArg(1)->getType());
----------------
vporpo wrote:

I think we are not testing the new `get()` functions:
```
// get(ElementType, NumElements, Scalable)
EXPECT_EQ(VectorType::get(Type::getInt16Ty(Ctx), 4, **/*Scalable=*/false), F>getArg(0)->getType());

// get(ElementType, Other)
EXPECT_EQ(VectorType::get(Type::getInt16Ty(Ctx), F->getArg(0)->getType()), F->getArg(0)->getType());

```

https://github.com/llvm/llvm-project/pull/107650