remove shares during withdraw in MockHyperdriveTestnet

[wakamex]

fixes: #417

[github-actions]

Hyperdrive Gas Benchmark

Benchmark suite	Current: ab4a1c6	Previous: 0db7112	Deviation	Status
addLiquidity: min	709 gas	709 gas	0%	🟰
addLiquidity: avg	45065 gas	46538 gas	-3.1652%	✅
addLiquidity: max	83400 gas	83400 gas	0%	🟰
checkpoint: min	514 gas	514 gas	0%	🟰
checkpoint: avg	23022 gas	23022 gas	0%	🟰
checkpoint: max	33418 gas	33418 gas	0%	🟰
closeLong: min	659 gas	659 gas	0%	🟰
closeLong: avg	46609 gas	46384 gas	0.4851%	🚨
closeLong: max	80866 gas	81764 gas	-1.0983%	✅
closeShort: min	616 gas	616 gas	0%	🟰
closeShort: avg	41557 gas	41556 gas	0.0024%	🚨
closeShort: max	81627 gas	81627 gas	0%	🟰
initialize: min	529 gas	529 gas	0%	🟰
initialize: avg	139316 gas	139316 gas	0%	🟰
initialize: max	140816 gas	140816 gas	0%	🟰
openLong: min	661 gas	661 gas	0%	🟰
openLong: avg	116575 gas	115004 gas	1.3660%	🚨
openLong: max	175672 gas	175672 gas	0%	🟰
openShort: min	709 gas	709 gas	0%	🟰
openShort: avg	158878 gas	161206 gas	-1.4441%	✅
openShort: max	218571 gas	218571 gas	0%	🟰
removeLiquidity: min	569 gas	569 gas	0%	🟰
removeLiquidity: avg	59987 gas	60031 gas	-0.0733%	✅
removeLiquidity: max	116368 gas	116368 gas	0%	🟰

This comment was automatically generated by workflow using github-action-benchmark.

[coveralls]

coverage: 97.489%. remained the same when pulling ab4a1c6 on wakamex/remove_shares_on_withdraw_in_MockHyperdriveTestnet into 0db7112 on main.