[Dive] Give more information about node values

src/plugins/dive/build.ml

src/plugins/dive/graph_types.mli

src/plugins/dive/imprecision_graph.ml

src/plugins/dive/imprecision_graph.mli

src/plugins/dive/tests/dive/oracle/assigned_param.dot

src/plugins/dive/tests/dive/oracle/assigned_param.res.oracle

src/plugins/dive/tests/dive/oracle/const.dot

src/plugins/dive/tests/dive/oracle/const.res.oracle

src/plugins/dive/tests/dive/oracle/global.res.oracle

src/plugins/dive/tests/dive/oracle/pointed_param.dot

src/plugins/dive/tests/dive/oracle/pointed_param.res.oracle

...ugins/dive/tests/dive/oracle/pointers_to_local.res.oracle

...ugins/dive/tests/dive/oracle/unfocused_callers.res.oracle

src/plugins/dive/tests/dive/oracle/various.dot

src/plugins/dive/tests/dive/oracle/various.res.oracle