added option to edgesplit bmesh operator to take tagged vertices as well so an edge at a boundary can split without splitting off the boundary vertex.
the behavior/speed of the edge split modifier and tool remainss the same, this is only used for rip.
this fixes but [#30461] where the same vertex was added to some faces twice.
Previous code rebuilt all faces around the split edges, replace this with much simpler code that uses existing bmesh API for splitting.
This also gives a performance boost to the modifier (over 30x faster in the bug-report file).
turns out old code also had the same bug (just coincidance it was noticed after my change)
now boundry verts are tagged so edges connected to them are not seen is missing a tagged, adjacent edge.
this fixes [#30471]
* optimize BM_face_other_edge_loop to do about half as many iterations for quad heavy meshes, with ngons the gain is much more since searching around the entire ngon when the edge already stores its loop is silly.
... also nicer in cases where edge has no face users it avoids a loop on all face corners.
* name bmesh operator func's BMO_slot_buffer_* rather then BMO_slot_* since it wasnt obvious some only dealt with buffer, some both.
* more typechecks and asserts of BMO_ functions (I lost some time calling a map with a buffer function that failed silently).
* small speedup for extrude check - test if the edge is wire _before_ doign a hash lookup.
