Tests: tune when GC runs

It's only needed for a few tests, what we were doing was drastic overkill, especially with background concurrent GC in play these days.

StackExchange.Redis.Tests/Profiling.cs

@@ -298,7 +298,7 @@ public async Task LeaksCollectedAndRePooled()
                 var anyContext = LeaksCollectedAndRePooled_Initialize(conn, ThreadCount);
 
                 // force collection of everything but `anyContext`
-                GC.Collect(3, GCCollectionMode.Forced, blocking: true);
+                GC.Collect(3, GCCollectionMode.Forced);
                 GC.WaitForPendingFinalizers();
 
                 await Task.Delay(TimeSpan.FromMinutes(1.01)).ForAwait();

StackExchange.Redis.Tests/PubSub.cs

@@ -270,9 +270,6 @@ private void TestMassivePublish(ISubscriber conn, string channel, string caption
         {
             const int loop = 10000;
 
-            GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
-            GC.WaitForPendingFinalizers();
-
             var tasks = new Task[loop];
 
             var withFAF = Stopwatch.StartNew();
@@ -282,9 +279,6 @@ private void TestMassivePublish(ISubscriber conn, string channel, string caption
             }
             withFAF.Stop();
 
-            GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
-            GC.WaitForPendingFinalizers();
-
             var withAsync = Stopwatch.StartNew();
             for (int i = 0; i < loop; i++)
             {

StackExchange.Redis.Tests/Scripting.cs

@@ -464,7 +464,6 @@ public void CompareScriptToDirect()
 
                 // run via script
                 db.KeyDelete(key, CommandFlags.FireAndForget);
-                CollectGarbage();
                 var watch = Stopwatch.StartNew();
                 for (int i = 1; i < LOOP; i++) // the i=1 is to do all-but-one
                 {
@@ -476,7 +475,6 @@ public void CompareScriptToDirect()
 
                 // run via raw op
                 db.KeyDelete(key, CommandFlags.FireAndForget);
-                CollectGarbage();
                 watch = Stopwatch.StartNew();
                 for (int i = 1; i < LOOP; i++) // the i=1 is to do all-but-one
                 {
@@ -750,9 +748,7 @@ public void PurgeLuaScriptOnFinalize()
             // This has to be a separate method to guarantee that the created LuaScript objects go out of scope,
             //   and are thus available to be GC'd
             _PurgeLuaScriptOnFinalize(Script);
-
-            GC.Collect(2, GCCollectionMode.Forced, blocking: true);
-            GC.WaitForPendingFinalizers();
+            CollectGarbage();
 
             Assert.Equal(0, LuaScript.GetCachedScriptCount());
 

StackExchange.Redis.Tests/TestBase.cs

@@ -47,11 +47,9 @@ protected void Log(string message, params object[] args)
 
         protected void CollectGarbage()
         {
-            for (int i = 0; i < 3; i++)
-            {
-                GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
-                GC.WaitForPendingFinalizers();
-            }
+            GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
+            GC.WaitForPendingFinalizers();
+            GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
         }
 
         [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1063:ImplementIDisposableCorrectly")]
@@ -113,7 +111,6 @@ protected void OnInternalError(object sender, InternalErrorEventArgs e)
 
         public void ClearAmbientFailures()
         {
-            Collect();
             Interlocked.Exchange(ref privateFailCount, 0);
             lock (sharedFailCount)
             {
@@ -135,18 +132,8 @@ public void SetExpectedAmbientFailureCount(int count)
             expectedFailCount = count;
         }
 
-        private static void Collect()
-        {
-            for (int i = 0; i < GC.MaxGeneration; i++)
-            {
-                GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced, true);
-                GC.WaitForPendingFinalizers();
-            }
-        }
-
         public void Teardown()
         {
-            Collect();
             int sharedFails;
             lock (sharedFailCount)
             {