Deparse: exclude two new test files

Add a couple of recently-added test files to

    Porting/deparse-skips.txt

These two test files have

    use utf8;
    "some string with accented chars"

and the accented char gets deparsed wrongly at the moment.
So skip those test files under

    cd t; ./TEST -deparse

Author: iabyn

Porting/deparse-skips.txt

@@ -273,7 +273,11 @@ uni/variables.t
 ../ext/XS-APItest/t/call_checker.t
 ../ext/XS-APItest/t/cleanup.t
 ../ext/XS-APItest/t/fetch_pad_names.t
+../ext/XS-APItest/t/regex_global_pos.t  # string literals under 'use utf8'
+                                        # are deparsed wrongly
 ../ext/XS-APItest/t/synthetic_scope.t
+../ext/XS-APItest/t/valid_identifier.t  # string literals under 'use utf8'
+                                        # are deparsed wrongly
 ../lib/Config.t                         # Config_heavy.pl fns getting output
 ../lib/charnames.t
 ../lib/dumpvar.t