bootstrap:table: sparse hash table: quadratic indexing: use & not %
bootstrap:table: sparse hash table: quadratic indexing: use & not %

We save over 10% in ./ncc0 total runtime with the fix of this stupid
oversight. The size of the underlying sparse table is always a power of
2 so we can use a bitwise op.

nanocritical/n,nanocritical/n,nanocritical/n,nanocritical/n