[llvm] [Offload] Replace "EventOut" parameters with `olCreateEvent` (PR #150217)

[Joseph Huber via llvm-commits]

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@@ -10,6 +10,17 @@
 //
 //===----------------------------------------------------------------------===//
 
+def : Function {
+    let name = "olCreateEvent";
+    let desc = "Create an event that will resolve when all current work in the queue is complete.";
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jhuber6 wrote:

Name seems kind of generic, this is a special event that waits on everything above it or something?

https://github.com/llvm/llvm-project/pull/150217