[interchange/parsing-improvements] Catch another case with UTF8 flag flipping seen in the wild

commit a243278912f021a9c6da3b0fc9b889d3b7de42b3
Author: David Christensen <[email protected]>
Date:   Fri Nov 17 13:42:56 2017 -0600

    Catch another case with UTF8 flag flipping seen in the wild

 lib/Vend/Interpolate.pm |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/lib/Vend/Interpolate.pm b/lib/Vend/Interpolate.pm
index a71b889..8e65a1e 100644
--- a/lib/Vend/Interpolate.pm
+++ b/lib/Vend/Interpolate.pm
@@ -665,6 +665,12 @@ sub interpolate_html {
 	vars_and_comments(\$html)
 		unless $opt and $opt->{onfly};
 
+	# catch potential flipped UTF8 flag from vars_and_comments
+	if (utf8::is_utf8($html)) {
+		$was_utf8 = 1;
+		Encode::_utf8_off($html)
+	}
+
 	$^W = 1 if $::Pragma->{perl_warnings_in_page};
 
     # Returns, could be recursive