Write to null stream before write to actual file.

Author: timcassell

src/BenchmarkDotNet.Weaver/src/WeaveAssemblyTask.cs

@@ -64,6 +64,9 @@ public override bool Execute()
 
             if (benchmarkMethodsImplAdjusted)
             {
+                // Write to a null stream before overwriting the original file in case an exception occurs during the write (like unsupported platform).
+                // https://github.com/Washi1337/AsmResolver/issues/640
+                module.Write(Stream.Null);
                 module.Write(TargetAssembly);
             }
         }