Make further use of new bitmapset code: executor's chgParam, extParam,

Make further use of new bitmapset code: executor's chgParam, extParam,
locParam lists can be converted to bitmapsets to speed updating.  Also,
replace 'locParam' with 'allParam', which contains all the paramIDs
relevant to the node (i.e., the union of extParam and locParam); this
saves a step during SetChangedParamList() without costing anything
elsewhere.