[llvm] [Offload] Add `MAX_WORK_GROUP_SIZE` device info query (PR #143718)

[Callum Fare via llvm-commits]

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@@ -247,11 +244,50 @@ Error olGetDeviceInfoImplDetail(ol_device_handle_t Device,
                                DevInfo.getQueue().end(), InfoKeyMatches);
 
       if (Item != std::end(DevInfo.getQueue())) {
-        return Item->Value;
+        return Item;
       }
     }
 
-    return std::string("");
+    return std::nullopt;
+  };
+  auto GetInfoString = [&](std::vector<std::string> Names) {
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callumfare wrote:

We should pass `Names` by reference here and in `GetInfoXyz` (I think this is my mistake from the original implementation)

Is there a reason we can't use `StringRef` and `SmallVector` here as well?

https://github.com/llvm/llvm-project/pull/143718