Ignore trailing blocks with a non-zero next block pointer

While the client doesn't appear to be capable of producing a trailing
block with a non-zero next block pointer (though I may have misread the
code), there are caches out there in the wild with trailing non-zero
next block pointers.

When it is reading a group, the client ignores these.

Therefore, for compatibility with the client and existing caches, this
commit removes the StoreCorruptException thrown in this case.

Signed-off-by: Graham <gpe@openrs2.org>

cache/src/main/kotlin/org/openrs2/cache/DiskStore.kt

@@ -196,10 +196,6 @@ public class DiskStore private constructor(
                     num++
                 } while (buf.isWritable)
 
-                if (block != 0) {
-                    throw StoreCorruptException("Group longer than expected")
-                }
-
                 return buf.retain()
             }
         }

cache/src/test/kotlin/org/openrs2/cache/DiskStoreTest.kt

@@ -495,12 +495,6 @@ class DiskStoreTest {
 
     @Test
     fun testReadCorrupt() {
-        readTest("corrupt-eof-late") { store ->
-            assertFailsWith<StoreCorruptException> {
-                store.read(255, 1).release()
-            }
-        }
-
         readTest("corrupt-first-eof-early") { store ->
             assertFailsWith<StoreCorruptException> {
                 store.read(255, 1).release()
@@ -562,6 +556,17 @@ class DiskStoreTest {
         }
     }
 
+    @Test
+    fun testReadCorruptEofLate() {
+        readTest("corrupt-eof-late") { store ->
+            copiedBuffer("OpenRS2".repeat(1000)).use { expected ->
+                store.read(255, 1).use { actual ->
+                    assertEquals(expected, actual)
+                }
+            }
+        }
+    }
+
     @Test
     fun testOverwriteCorrupt() {
         overwriteTest("corrupt-eof-late", "corrupt-eof-late-overwritten") { store ->