Fix ordering of adding in Regex's BitVector.GetHashCode (#71913)

It's slightly cheaper to call AddBytes before Add(int).

diff --git a/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/Symbolic/BitVector.cs b/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/Symbolic/BitVector.cs
index edfeac5..4eda223 100644 (file)
--- a/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/Symbolic/BitVector.cs
+++ b/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/Symbolic/BitVector.cs
@@ -175,12 +175,8 @@ namespace System.Text.RegularExpressions.Symbolic
             if (_hashcode == null)
             {
                 HashCode hc = default;
+                hc.AddBytes(MemoryMarshal.AsBytes<ulong>(_blocks));
                 hc.Add(Length);
-                if (_blocks is ulong[] blocks) // may be null in case of a default struct
-                {
-                    hc.AddBytes(MemoryMarshal.AsBytes<ulong>(blocks));
-                }
-
                 _hashcode = hc.ToHashCode();
             }