Data-Dumper: fix dumpperl.t for non-XS testing

This is a follow-up to commit b5048e7,
which added 'Deparse' support to XS, and commit
9baac1a, which added 'Useqq' support to
XS. There are no longer any configuration settings that implicitly force
the use of the pure Perl implementation (outside of 'Useperl' itself).

Previously, testing without XS available resulted in:

    t/dumpperl.t .................. 1/31 Undefined subroutine &Data::Dumper::Dumpxs called at .../dist/Data-Dumper/blib/lib/Data/Dumper.pm line 213.
    # Looks like your test exited with 255 just after 10.
    t/dumpperl.t .................. Dubious, test returned 255 (wstat 65280, 0xff00)
    Failed 21/31 subtests
    ...
    t/dumpperl.t                (Wstat: 65280 (exited 255) Tests: 10 Failed: 0)
      Non-zero exit status: 255
      Parse errors: Bad plan.  You planned 31 tests but ran 10.

Author: mauke

dist/Data-Dumper/t/dumpperl.t

@@ -6,7 +6,7 @@ use warnings;
 
 use Carp;
 use Data::Dumper;
-use Test::More tests => 31;
+use Test::More tests => 11;
 use lib qw( ./t/lib );
 use Testing qw( _dumptostr );
 
@@ -20,23 +20,7 @@ $Data::Dumper::Indent=1;
     run_tests_for_pure_perl_implementations();
 }
 
-{
-    local $Data::Dumper::Useperl=0;
-    local $Data::Dumper::Useqq=1;
-    local $Data::Dumper::Deparse=0;
-    note('$Data::Dumper::Useqq => 1');
-    run_tests_for_pure_perl_implementations();
-}
-    
-{
-    local $Data::Dumper::Useperl=0;
-    local $Data::Dumper::Useqq=0;
-    local $Data::Dumper::Deparse=1;
-    note('$Data::Dumper::Deparse => 1');
-    run_tests_for_pure_perl_implementations();
-}
-    
-    
+
 
 sub run_tests_for_pure_perl_implementations {