Fix an 'attempt to shift right with overflow' panic in the GnuHashTable if nshift is wider than the bloom filter word size

This changes the case to be an IntegerOverflow error instead of a crash/panic by using checked_shr

This was found by fuzz testing

src/hash.rs

@@ -280,10 +280,14 @@ impl<'data, E: EndianParse> GnuHashTable<'data, E> {
             }
         };
 
+        // Check bloom filter for both hashes - symbol is present in the hash table IFF both bits are set.
         if filter & (1 << (hash % bloom_width)) == 0 {
             return Ok(None);
         }
-        if filter & (1 << ((hash >> self.hdr.nshift) % bloom_width)) == 0 {
+        let hash2 = hash
+            .checked_shr(self.hdr.nshift)
+            .ok_or(ParseError::IntegerOverflow)?;
+        if filter & (1 << (hash2 % bloom_width)) == 0 {
             return Ok(None);
         }