Force the overflow in BitVectorCoding::skipTo to be 64-bit
Force the overflow in BitVectorCoding::skipTo to be 64-bit

Summary: This code was relying on the `- 1` overflowing as a 64-bit value, but MSVC (correctly in my opinion) was overflowing this as a 32-bit value, resulting in a segfault when trying to run the bitvector and eliasfano tests on MSVC.

Reviewed By: yfeldblum

Differential Revision: D3652343

fbshipit-source-id: 38a22abfc0d05ab2f070c450eebfa69af07d26af

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