Use fresh_perl_like for op/warn.t

GH #57

this is fixing two subtests but the test
is still broken for other reasons: utf8 layer.

t/v5.24.1/C-COMPILED/known_errors.txt

@@ -46,7 +46,7 @@ op/sub_lval.t          TESTS     BC issue #277 - sub declaration with :lvalue sh
 op/svleak.t            COMPAT    This test uses XS::APItest, which we don't install during perl install?
 op/threads-dirh.t      COMPAT    We don't support threaded perl in this branch.
 op/threads.t           COMPAT    We don't support threaded perl in this branch.
-op/warn.t              TESTS     BC issue #219 - overload issue
+op/warn.t              TESTS     GH #57 - open qw(:std :utf8) STDOUT issue
 op/yadayada.t          COMPAT    Unimplemented does not display the correct line number
 opbasic/magic_phase.t  COMPAT    Testing BEGIN, INIT, ... phases order, not compatible with B::C
 re/overload.t          TESTS     ?? + BC issue #219 - overload issue

t/v5.24.1/t/op/warn.t

@@ -195,7 +195,7 @@ eval "#line 42 Cholmondeley\n \$\@ = 3; warn";
 is @warnings, 2;
 is $warnings[1], $warnings[0], 'warn treats $@=3 and $@="3" the same way';
 
-fresh_perl_is(<<'EOF', "should be line 4 at - line 4.\n", {stderr => 1}, "");
+fresh_perl_like(<<'EOF', qr{should be line 4 at .* line 4\.}, {stderr => 1}, "");
 ${
     foo
 } = "should be line 4";
@@ -204,13 +204,11 @@ EOF
 
 TODO: {
     local $::TODO = "Line numbers don't yet match up for \${ EXPR }";
-    my $expected = <<'EOF';
-line 1 at - line 1.
-line 4 at - line 3.
-also line 4 at - line 4.
-line 5 at - line 5.
-EOF
-    fresh_perl_is(<<'EOF', $expected, {stderr => 1}, "");
+    my $expected = qr{line 1 at .* line 1.
+line 4 at .* line 2.
+also line 4 at .* line 4.
+line 5 at .* line 5.}m;
+    fresh_perl_like(<<'EOF', $expected, {stderr => 1}, "");
 warn "line 1";
 (${
     foo