Remove the property disabling optimization (#19701)

src/System.Management.Automation/CoreCLR/CorePsPlatform.cs

@@ -932,8 +932,10 @@ namespace System.Management.Automation
                 [LibraryImport(psLib)]
                 internal static partial int WaitPid(int pid, [MarshalAs(UnmanagedType.Bool)] bool nohang);
 
-                // This is a struct tm from <time.h>.
-                [StructLayout(LayoutKind.Sequential)]
+                // This is the struct `private_tm` from setdate.h in libpsl-native.
+                // Packing is set to 4 to match the unmanaged declaration.
+                // https://github.com/PowerShell/PowerShell-Native/blob/c5575ceb064e60355b9fee33eabae6c6d2708d14/src/libpsl-native/src/setdate.h#L23
+                [StructLayout(LayoutKind.Sequential, Pack = 4)]
                 internal unsafe struct UnixTm
                 {
                     /// <summary>Seconds (0-60).</summary>
@@ -980,7 +982,7 @@ namespace System.Management.Automation
                     return tm;
                 }
 
-                [LibraryImport(psLib)]
+                [LibraryImport(psLib, SetLastError = true)]
                 internal static unsafe partial int SetDate(UnixTm* tm);
 
                 [LibraryImport(psLib, StringMarshalling = StringMarshalling.Utf8)]