* data/push.c (yypush_parse): Set yynew = 1 at the end of a parse

* data/push.c (yypush_parse): Set yynew = 1 at the end of a parse
(whether successful or failed) so that yypush_parse can be invoked
again to start a new parse using the same yypstate.
* tests/torture.at (AT_DATA_STACK_TORTURE): For push mode, extend to
check multiple yypull_parse invocations on the same yypstate.  For pull
mode, extend to check multiple yyparse invocations.
(Exploding the Stack Size with Alloca): Extend to try with
%push-pull-parser.
(Exploding the Stack Size with Malloc): Likewise.

* tests/calc.at (Simple LALR Calculator): Don't specify
%skeleton "push.c" since %push-pull-parser implies that now.
* tests/headers.at (export YYLTYPE): Don't check for the push
declarations.  Otherwise, this test case can't be used to see if push
mode can truly emulate pull mode.
* tests/input.at (Torturing the Scanner): Likewise.
* tests/local.at (AT_YACC_OR_PUSH_IF, AT_PUSH_IF): Remove.
(AT_YYERROR_SEES_LOC_IF): Rather than AT_YACC_OR_PUSH_IF, use
AT_YACC_IF, which now includes the case of push mode since %skeleton
need not be used for push mode.  This will be more intuitive once
push.c is renamed to yacc.c.