fix: allow 0 capacity for table

- Added guards at the bucket level, to ensure that getting an item in an empty bucket doesn't cause an error.
- Added grow() and shrink() functions to Table, to prevent a capacity of 0 from not being able to grow.
- Updated the fuzz test to use `go_fuzz-utils`.

testdata/fuzz/FuzzInsertLookup/663e746d1518e2f5

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("B000000000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000")