Enable CA1837: Use 'Environment.ProcessId' (#14063)

https://docs.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1837

src/System.Management.Automation/engine/InformationRecord.cs

@@ -137,7 +137,7 @@ namespace System.Management.Automation
             {
                 if (!this._processId.HasValue)
                 {
-                    this._processId = (uint)System.Diagnostics.Process.GetCurrentProcess().Id;
+                    this._processId = (uint)Environment.ProcessId;
                 }
 
                 return this._processId.Value;

src/System.Management.Automation/engine/hostifaces/MshHostUserInterface.cs

@@ -511,7 +511,7 @@ namespace System.Management.Automation.Host
                         Environment.MachineName,
                         Environment.OSVersion.VersionString,
                         string.Join(" ", Environment.GetCommandLineArgs()),
-                        System.Diagnostics.Process.GetCurrentProcess().Id,
+                        Environment.ProcessId,
                         versionInfoFooter.ToString().TrimEnd());
             }
 

src/System.Management.Automation/engine/remoting/commands/EnterPSHostProcessCommand.cs

@@ -377,7 +377,7 @@ namespace Microsoft.PowerShell.Commands
 
         private void VerifyProcess(Process process)
         {
-            if (process.Id == Process.GetCurrentProcess().Id)
+            if (process.Id == Environment.ProcessId)
             {
                 ThrowTerminatingError(
                         new ErrorRecord(

src/System.Management.Automation/engine/remoting/common/RemoteSessionNamedPipe.cs

@@ -744,7 +744,7 @@ namespace System.Management.Automation.Remoting
         [SuppressMessage("Microsoft.Reliability", "CA2001:AvoidCallingProblematicMethods", MessageId = "System.Runtime.InteropServices.SafeHandle.DangerousGetHandle")]
         private void ProcessListeningThread(object state)
         {
-            string processId = System.Diagnostics.Process.GetCurrentProcess().Id.ToString(CultureInfo.InvariantCulture);
+            string processId = Environment.ProcessId.ToString(CultureInfo.InvariantCulture);
             string appDomainName = NamedPipeUtils.GetCurrentAppDomainName();
 
             // Logging.