Route the base DataInput VInt throws through the VIntUtils helpers too, #1279

For consistency with the concrete-reader overrides, the base ReadVInt32/64 slow
path now calls the non-inlined VIntUtils.ThrowInvalidVInt32/64() helpers rather
than throwing inline. Addresses PR #1345 review feedback.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: paulirwin

src/Lucene.Net/Store/DataInput.cs

@@ -1,6 +1,7 @@
 using J2N.Numerics;
 using J2N.Text;
 using Lucene.Net.Diagnostics;
+using Lucene.Net.Support;
 using Lucene.Net.Support.Buffers;
 using Lucene.Net.Util;
 using System;
@@ -198,7 +199,8 @@ public virtual int ReadVInt32()
             {
                 return i;
             }
-            throw new IOException("Invalid VInt32 detected (too many bits)");
+            VIntUtils.ThrowInvalidVInt32();
+            return 0; // unreachable; ThrowInvalidVInt32 always throws
         }
 
         /// <summary>
@@ -295,7 +297,8 @@ public virtual long ReadVInt64()
             {
                 return i;
             }
-            throw new IOException("Invalid VInt64 detected (negative values disallowed)");
+            VIntUtils.ThrowInvalidVInt64();
+            return 0; // unreachable; ThrowInvalidVInt64 always throws
         }
 
 #nullable enable

src/Lucene.Net/Support/VIntUtils.cs

@@ -191,7 +191,8 @@ public static bool TryReadVInt64(ReadOnlySpan<byte> source, out long value, out
 
         /// <summary>
         /// Throws an <see cref="IOException"/> indicating a malformed 32-bit VInt. Used by the
-        /// buffered/stream-backed readers, which surface decode failures as I/O errors.
+        /// base <see cref="Lucene.Net.Store.DataInput"/> and the buffered/stream-backed readers,
+        /// which surface decode failures as I/O errors.
         /// </summary>
         [MethodImpl(MethodImplOptions.NoInlining)]
         [DoesNotReturn]
@@ -200,7 +201,8 @@ public static void ThrowInvalidVInt32()
 
         /// <summary>
         /// Throws an <see cref="IOException"/> indicating a malformed 64-bit VInt. Used by the
-        /// buffered/stream-backed readers, which surface decode failures as I/O errors.
+        /// base <see cref="Lucene.Net.Store.DataInput"/> and the buffered/stream-backed readers,
+        /// which surface decode failures as I/O errors.
         /// </summary>
         [MethodImpl(MethodImplOptions.NoInlining)]
         [DoesNotReturn]