fix an ambiguity in the grammar from the implementation of extended unpacking

(one which was strangely "resolved" by pgen)

This also kills the unused testlist1 rule and fixes parse tree validation of
extended unpacking.

Lib/symbol.py

@@ -26,69 +26,69 @@ stmt = 268
 simple_stmt = 269
 small_stmt = 270
 expr_stmt = 271
-augassign = 272
-del_stmt = 273
-pass_stmt = 274
-flow_stmt = 275
-break_stmt = 276
-continue_stmt = 277
-return_stmt = 278
-yield_stmt = 279
-raise_stmt = 280
-import_stmt = 281
-import_name = 282
-import_from = 283
-import_as_name = 284
-dotted_as_name = 285
-import_as_names = 286
-dotted_as_names = 287
-dotted_name = 288
-global_stmt = 289
-nonlocal_stmt = 290
-assert_stmt = 291
-compound_stmt = 292
-if_stmt = 293
-while_stmt = 294
-for_stmt = 295
-try_stmt = 296
-with_stmt = 297
-with_item = 298
-except_clause = 299
-suite = 300
-test = 301
-test_nocond = 302
-lambdef = 303
-lambdef_nocond = 304
-or_test = 305
-and_test = 306
-not_test = 307
-comparison = 308
-comp_op = 309
-star_expr = 310
-expr = 311
-xor_expr = 312
-and_expr = 313
-shift_expr = 314
-arith_expr = 315
-term = 316
-factor = 317
-power = 318
-atom = 319
-testlist_comp = 320
-trailer = 321
-subscriptlist = 322
-subscript = 323
-sliceop = 324
-exprlist = 325
-testlist = 326
-dictorsetmaker = 327
-classdef = 328
-arglist = 329
-argument = 330
-comp_iter = 331
-comp_for = 332
-comp_if = 333
-testlist1 = 334
+testlist_star_expr = 272
+augassign = 273
+del_stmt = 274
+pass_stmt = 275
+flow_stmt = 276
+break_stmt = 277
+continue_stmt = 278
+return_stmt = 279
+yield_stmt = 280
+raise_stmt = 281
+import_stmt = 282
+import_name = 283
+import_from = 284
+import_as_name = 285
+dotted_as_name = 286
+import_as_names = 287
+dotted_as_names = 288
+dotted_name = 289
+global_stmt = 290
+nonlocal_stmt = 291
+assert_stmt = 292
+compound_stmt = 293
+if_stmt = 294
+while_stmt = 295
+for_stmt = 296
+try_stmt = 297
+with_stmt = 298
+with_item = 299
+except_clause = 300
+suite = 301
+test = 302
+test_nocond = 303
+lambdef = 304
+lambdef_nocond = 305
+or_test = 306
+and_test = 307
+not_test = 308
+comparison = 309
+comp_op = 310
+star_expr = 311
+expr = 312
+xor_expr = 313
+and_expr = 314
+shift_expr = 315
+arith_expr = 316
+term = 317
+factor = 318
+power = 319
+atom = 320
+testlist_comp = 321
+trailer = 322
+subscriptlist = 323
+subscript = 324
+sliceop = 325
+exprlist = 326
+testlist = 327
+dictorsetmaker = 328
+classdef = 329
+arglist = 330
+argument = 331
+comp_iter = 332
+comp_for = 333
+comp_if = 334
 encoding_decl = 335
 yield_expr = 336
 #--end constants--