Cover ConfigureAwait in the Async pretty test fixture.

Two methods exercise `Task<int>.ConfigureAwait(bool)`: a single false-flag
form and a mixed false/true form that combines two awaits in a return
expression. Both cases run through the regular state-machine and runtime-async
pipelines (RuntimeAsync reuses Async.cs as its source).

Gated by `#if ROSLYN2` because Roslyn 2+ preserves named-argument metadata at
the call site, so the decompiler renders `continueOnCapturedContext: false`
when the binary was compiled by Roslyn 2+ and positional `false` for
default csc / Roslyn 1.3.2.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: siegfriedpammer

ICSharpCode.Decompiler.Tests/TestCases/Pretty/Async.cs

@@ -74,6 +74,12 @@ public async Task SimpleVoidTaskMethod()
 			Console.WriteLine("After");
 		}
 
+		[MethodImpl(MethodImplOptions.NoInlining)]
+		public async Task NoInliningTaskMethod()
+		{
+			await Task.Yield();
+		}
+
 		public async Task TaskMethodWithoutAwait()
 		{
 			Console.WriteLine("No Await");
@@ -115,6 +121,24 @@ public async void AwaitInLoopCondition()
 			}
 		}
 
+		public async Task AwaitConfigureAwaitFalse(Task<int> task)
+		{
+#if ROSLYN2
+			Console.WriteLine(await task.ConfigureAwait(continueOnCapturedContext: false));
+#else
+			Console.WriteLine(await task.ConfigureAwait(false));
+#endif
+		}
+
+		public async Task<int> AwaitConfigureAwaitMixed(Task<int> task1, Task<int> task2)
+		{
+#if ROSLYN2
+			return await task1.ConfigureAwait(continueOnCapturedContext: false) + await task2.ConfigureAwait(continueOnCapturedContext: true);
+#else
+			return await task1.ConfigureAwait(false) + await task2.ConfigureAwait(true);
+#endif
+		}
+
 #if CS60
 		public async Task AwaitInCatch(bool b, Task<int> task1, Task<int> task2)
 		{