Cover items to counters (#918)

Cover items to counters (#918)

* src: Move toggle coverage emit (recursive array traversal) to "cov-data" from lower.

* src: Linearize control flow in cover_add_toggle_items_for.

* src, test: Convert toggle coverage to separate cover_item for 0->1 and 1->0.

* src: Set "num" by default to 1 -> Becomes valid for statements. Simplify cover chain append logic for COV_ITEM_STMT.

* src: Move "num" setting for COV_ITEM_TOGGLE to better place.

* WIP: Branch coverage - Conversion to counters.

* src: Convert branch items fully to single item per covered item in reports too.

* src: Move bin name append for toggle items to cover_add_item.

* src: Move FSM state coverage logic to "cover" and make it counter, not flag.

* src: Fix typo in Button that gives you coverage exclude command.

* src: Move "num" setting for COV_ITEM_TOGGLE to better place.

* WIP: Branch coverage - Conversion to counters.

* src: Convert branch items fully to single item per covered item in reports too.

* src: Move bin name append for toggle items to cover_add_item.

* src: Port fixes from #909 and #906 to coverage refactoring.

* src, test: Rework expression coverage conversion to counters.

* src: Unify reporting of COV_ITEM_FUNCTIONAL to use new conversion to cover_chain_t.

* src: Remove Exclude mask from cov_item_t, now handled by single flag.

* src: Fix build on MACOS.

* src, test: Fix leak in the branch coverage.

* src: Rename "num" to "consecutive" to better correspond to its meaning.

* src, test: Get rid of the BIN in the exclude file completely.

* src, test: Clarify that simultaneous covered + excluded will result in covered.

* src: Unify "cover_add_*" API towards lower.

* src, test: Merge VCODE_OP_COVER_STMT, VCODE_OP_COVER_BRANCH and VCODE_OP_COVER_EXPRESSION.

* src, test: Rename "STATE" to "BIN_STATE" to have the same naming as rest of bins.

* NEWS, www: Update documentation and changes.

* Apply comments from review.

* Revert "src, test: Merge VCODE_OP_COVER_STMT, VCODE_OP_COVER_BRANCH and VCODE_OP_COVER_EXPRESSION."

This reverts commit 9daa3dc0fd1d3ba1e3e63e1e9b4d0b0c020b90ac.

* src: Remove unused variable.