[mlir:Async] Convert assertions to async errors only inside async functions

[mehdi_amini]

Can you add a test?

mlir/lib/Dialect/Async/Transforms/AsyncToAsyncRuntime.cpp

void AsyncToAsyncRuntimePass::runOnOperation() {
   asyncPatterns.add<AssertOpLowering>(ctx, outlinedFunctions);
 
   // All high level async operations must be lowered to the runtime operations.
   ConversionTarget runtimeTarget(*ctx);
   runtimeTarget.addLegalDialect<AsyncDialect>();
   runtimeTarget.addIllegalOp<CreateGroupOp, AddToGroupOp>();
   runtimeTarget.addIllegalOp<ExecuteOp, AwaitOp, AwaitAllOp, async::YieldOp>();
 
-  // Assertions must be converted to runtime errors.
-  runtimeTarget.addIllegalOp<AssertOp>();
+  // Assertions must be converted to runtime errors inside async functions.
+  runtimeTarget.addDynamicallyLegalOp<AssertOp>([&](AssertOp op) -> bool {
+    auto func = op->getParentOfType<FuncOp>();
+    return outlinedFunctions.find(func) == outlinedFunctions.end();
+  });
   runtimeTarget.addLegalOp<CondBranchOp>();
 
   if (failed(applyPartialConversion(module, runtimeTarget,
                                     std::move(asyncPatterns)))) {
     signalPassFailure();
     return;
   }
 }
 
 std::unique_ptr<OperationPass<ModuleOp>> mlir::createAsyncToAsyncRuntimePass() {
   return std::make_unique<AsyncToAsyncRuntimePass>();
 }