Do some cleanup on TimeSpan to ensure better inlining and clearer semantics

src/libraries/System.Private.CoreLib/src/System/ArgumentNullException.cs

@@ -59,6 +59,14 @@ public static void ThrowIfNull([NotNull] object? argument, [CallerArgumentExpres
             }
         }
 
+        internal static void ThrowIfNull([NotNull] object? argument, ExceptionArgument paramName)
+        {
+            if (argument is null)
+            {
+                ThrowHelper.ThrowArgumentNullException(paramName);
+            }
+        }
+
         /// <summary>Throws an <see cref="ArgumentNullException"/> if <paramref name="argument"/> is null.</summary>
         /// <param name="argument">The pointer argument to validate as non-null.</param>
         /// <param name="paramName">The name of the parameter with which <paramref name="argument"/> corresponds.</param>

src/libraries/System.Private.CoreLib/src/System/ThrowHelper.cs

@@ -89,6 +89,12 @@ internal static void ThrowArgumentException_DestinationTooShort()
             throw new ArgumentException(SR.Argument_DestinationTooShort, "destination");
         }
 
+        [DoesNotReturn]
+        internal static void ThrowArgumentException_InvalidTimeSpanStyles()
+        {
+            throw new ArgumentException(SR.Argument_InvalidTimeSpanStyles, "styles");
+        }
+
         [DoesNotReturn]
         internal static void ThrowArgumentException_OverlapAlignmentMismatch()
         {
@@ -224,12 +230,24 @@ internal static void ThrowOverflowException()
             throw new OverflowException();
         }
 
+        [DoesNotReturn]
+        internal static void ThrowOverflowException_NegateTwosCompNum()
+        {
+            throw new OverflowException(SR.Overflow_NegateTwosCompNum);
+        }
+
         [DoesNotReturn]
         internal static void ThrowOverflowException_TimeSpanTooLong()
         {
             throw new OverflowException(SR.Overflow_TimeSpanTooLong);
         }
 
+        [DoesNotReturn]
+        internal static void ThrowOverflowException_TimeSpanDuration()
+        {
+            throw new OverflowException(SR.Overflow_Duration);
+        }
+
         [DoesNotReturn]
         internal static void ThrowArgumentException_Arg_CannotBeNaN()
         {