Chore/hashcode combine (#2283)

* Revert "Inline HashCode.Combine polyfill (#2280)"

This reverts commit ccf63b5.

* Simplify

src/Sentry/Internal/Polyfills.cs

@@ -1,5 +1,16 @@
 // Polyfills to bridge the missing APIs in older targets.
 
+#if NETFRAMEWORK || NETSTANDARD2_0
+namespace System
+{
+    internal static class HashCode
+    {
+        public static int Combine<T1, T2>(T1 value1, T2 value2) => (value1, value2).GetHashCode();
+        public static int Combine<T1, T2, T3>(T1 value1, T2 value2, T3 value3) => (value1, value2, value3).GetHashCode();
+    }
+}
+#endif
+
 #if NETFRAMEWORK
 namespace System.Net.Http.Headers
 {

src/Sentry/MeasurementUnit.cs

@@ -82,21 +82,7 @@ internal static MeasurementUnit Parse(string? name)
     public override bool Equals(object? obj) => obj is MeasurementUnit other && Equals(other);
 
     /// <inheritdoc />
-    public override int GetHashCode()
-    {
-        var unitType = _unit?.GetType();
-#if NETSTANDARD2_0 || NETFRAMEWORK
-        unchecked
-        {
-            var hashCode = _unit != null ? _unit.GetHashCode() : 0;
-            hashCode = (hashCode * 397) ^ (_name != null ? _name.GetHashCode() : 0);
-            hashCode = (hashCode * 397) ^ (unitType != null ? unitType.GetHashCode() : 0);
-            return hashCode;
-        }
-#else
-        return HashCode.Combine(_unit, _name, unitType);
-#endif
-    }
+    public override int GetHashCode() => HashCode.Combine(_unit, _name, _unit?.GetType());
 
     /// <summary>
     /// Returns true if the operands are equal.
@@ -107,4 +93,4 @@ public override int GetHashCode()
     /// Returns true if the operands are not equal.
     /// </summary>
     public static bool operator !=(MeasurementUnit left, MeasurementUnit right) => !left.Equals(right);
-}
+}