Fix a contract violation in ThreadPool.get_CompletedWorkItemCount (#24535)

Fix a contract violation in ThreadPool.get_CompletedWorkItemCount

Fixes https://github.com/dotnet/coreclr/issues/24515
- Looks like the path that acquires the thread store lock has code that is marked witH GC_TRIGGERS
- Changed ThreadPool.get_CompletedWorkItemCount and Monitor.get_LockContentionCount to use QCalls instead of FCalls

2 files changed, 9 insertions, 10 deletions

diff --git a/src/System.Private.CoreLib/src/System/Threading/Monitor.cs b/src/System.Private.CoreLib/src/System/Threading/Monitor.cs
index a123f067e3..4385bf9992 100644
--- a/src/System.Private.CoreLib/src/System/Threading/Monitor.cs
+++ b/src/System.Private.CoreLib/src/System/Threading/Monitor.cs
@@ -20,6 +20,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.ConstrainedExecution;
 using System.Runtime.Versioning;
 using System.Diagnostics;
+using System.Runtime.InteropServices;
 
 namespace System.Threading
 {
@@ -236,10 +237,9 @@ namespace System.Threading
         /// <summary>
         /// Gets the number of times there was contention upon trying to take a <see cref="Monitor"/>'s lock so far.
         /// </summary>
-        public static extern long LockContentionCount
-        {
-            [MethodImpl(MethodImplOptions.InternalCall)]
-            get;
-        }
+        public static long LockContentionCount => GetLockContentionCount();
+
+        [DllImport(JitHelpers.QCall, CharSet = CharSet.Unicode)]
+        private static extern long GetLockContentionCount();
     }
 }
diff --git a/src/System.Private.CoreLib/src/System/Threading/ThreadPool.CoreCLR.cs b/src/System.Private.CoreLib/src/System/Threading/ThreadPool.CoreCLR.cs
index d7b2c2741a..eac84d4dbe 100644
--- a/src/System.Private.CoreLib/src/System/Threading/ThreadPool.CoreCLR.cs
+++ b/src/System.Private.CoreLib/src/System/Threading/ThreadPool.CoreCLR.cs
@@ -254,11 +254,10 @@ namespace System.Threading
         /// <remarks>
         /// For a thread pool implementation that may have different types of work items, the count includes all types.
         /// </remarks>
-        public static extern long CompletedWorkItemCount
-        {
-            [MethodImpl(MethodImplOptions.InternalCall)]
-            get;
-        }
+        public static long CompletedWorkItemCount => GetCompletedWorkItemCount();
+
+        [DllImport(JitHelpers.QCall, CharSet = CharSet.Unicode)]
+        private static extern long GetCompletedWorkItemCount();
 
         private static extern long PendingUnmanagedWorkItemCount
         {