Explicitly unset REPL env vars for the test

In case testing environment has them set for some reason.

t/02-rakudo/repl.t

@@ -15,14 +15,17 @@ my $*REPL-SCRUBBER = -> $_ is copy {
     $_
 }
 
-subtest 'sanity check; load without tweaking line editor' => {
-    plan 3;
-    my $p := run $*EXECUTABLE, '--repl-mode=interactive', :in, :out, :err;
-    $p.in.say: '133742.flip.say';
-    $p.in.close;
-    like $p.out.slurp(:close),     /247331/, 'result of code is on STDOUT';
-    is $p.err.slurp(:close).chars, 0,        'no STDERR output';
-    is $p.exitcode,                0,        'successful exit code';
+{
+    (temp %*ENV)<RAKUDO_ERROR_COLOR  RAKUDO_LINE_EDITOR>:delete;
+    subtest 'sanity check; load without tweaking line editor' => {
+        plan 3;
+        my $p := run $*EXECUTABLE, '--repl-mode=interactive', :in, :out, :err;
+        $p.in.say: '133742.flip.say';
+        $p.in.close;
+        like $p.out.slurp(:close),     /247331/, 'result of code is on STDOUT';
+        is $p.err.slurp(:close).chars, 0,        'no STDERR output';
+        is $p.exitcode,                0,        'successful exit code';
+    }
 }
 
 # RT #123187