Add the first 'Fixed in RakuAST' tests

In order to prevent regressions, we will be accumulating
test cases for issues that remain open but which have been
confirmed working with RakuAST.

First up: R#5520 (#5520) and R#5546 (#5546).

t/12-rakuast/fixed-in-rakuast.rakutest

@@ -0,0 +1,20 @@
+use Test;
+use lib <t/packages/Test-Helpers>;
+use Test::Helpers;
+
+plan 2;
+
+# S03-sequence/misc.t
+# https://github.com/rakudo/rakudo/issues/5520
+{
+    my @result;
+    Q| @result.push($_) for 1...5...3 |.AST.EVAL;
+    is-deeply @result, [1, 2, 3, 4, 5, 4, 3], ".say works with chained sequence and for";
+}
+
+# ???
+# https://github.com/rakudo/rakudo/issues/5546
+{
+    is-run 'Q| use trace; my %a{Str} |.AST.EVAL', :err("2 (EVAL_0 line 1)\nmy \%a\{Str} \n"),
+        "trace pragma works with hash shapes";
+}