test: PositionStatusFlag checks

[DhairyaSethi]

Add dedicated tests for position status flag change (+ event emission) on relevant actions.
ref: #462 (comment)

Also add tests which depend on the change in the status.

[miguelmtzinf]

Important to check collateral/borrowing flags when performing actions because those are source of truth on calculateUserAccountData and have a direct impact on collateralization of the system

[yan-man]

is this not a dupe of #484