Fix build for net7.0

Fails with:
```
src/tests/tracing/eventpipe/common/Microsoft.Diagnostics.NETCore.Client/DiagnosticsIpc/IpcSocket.cs(27,35): error CS0108: 'IpcSocket.AcceptAsync(CancellationToken)' hides inherited member 'Socket.AcceptAsync(CancellationToken)'. Use the new keyword if hiding was intended. [/__w/1/s/src/tests/tracing/eventpipe/common/Microsoft.Diagnostics.NETCore.Client/Microsoft.Diagnostics.NETCore.Client.csproj]
```

src/tests/tracing/eventpipe/common/Microsoft.Diagnostics.NETCore.Client/DiagnosticsIpc/IpcSocket.cs

@@ -23,7 +23,7 @@ public IpcSocket(AddressFamily addressFamily, SocketType socketType, ProtocolTyp
         }
 
 // .NET 6 implements this method directly on Socket, but for earlier runtimes we need a polyfill
-#if !NET6_0
+#if !NET6_0_OR_GREATER
         public async Task<Socket> AcceptAsync(CancellationToken token)
         {
             using (token.Register(() => Close(0)))
@@ -63,7 +63,7 @@ public virtual void Connect(EndPoint remoteEP, TimeSpan timeout)
         }
 
 // .NET 6 implements this method directly on Socket, but for earlier runtimes we need a polyfill
-#if !NET6_0
+#if !NET6_0_OR_GREATER
         public async Task ConnectAsync(EndPoint remoteEP, CancellationToken token)
         {
             using (token.Register(() => Close(0)))