Add test for the extended alternative forms of 42.:<->

This commit add more in depth testing of issue Rakudo/#2094 on GitHub.
In particular, it checks support of 42.:['-'], 42.:«"-"» and similar
forms.

This commit also switches to eval-lives-ok from just ok to fail
elegantly instead of crashing when the implementation does not support
these alternative forms.

S02-literals/numeric.t

@@ -124,8 +124,12 @@ ok 0e999999999999999 == 0, '0e999999999999 equals zero';
 
 # https://github.com/rakudo/rakudo/issues/2094
 subtest '#2094 prefix as post fix works on number literals' => {
-   plan 2;
-   ok 42.:<-> == -42, 'use negation as postfix';
-   ok 42.:<~> === "42", 'use ~ as postfix';
+   plan 6;
+   eval-lives-ok q{42.:<-> == -42}, 'use negation as postfix';
+   eval-lives-ok q{42.:<~> === "42"}, 'use ~ as postfix';
+   eval-lives-ok q{42.:«~» === "42"}, 'use « » to wrap the prefix';
+   eval-lives-ok q{42.:<<~>> === "42"}, 'use << >> to wrap the prefix';
+   eval-lives-ok q{42.:["~"] === "42"}, 'use [" "] to wrap the prefix';
+   eval-lives-ok q{42.:<<'~'>> === "42"}, "use <<' '>> to wrap the prefix";
 }
 # vim: ft=perl6 sw=4 ts=4 expandtab