Fix a bug in printing of string literals with escape sequences.

testcases/type-propagation/stringliteral.baseline.txt

Index: testcases/type-propagation/stringliteral.baseline.txt
diff --git a/testcases/type-propagation/stringliteral.baseline.txt b/testcases/type-propagation/stringliteral.baseline.txt
new file mode 100644
index 0000000000000000000000000000000000000000..ded8c03629c5fa015f68eeebce5d71f9aec6a687
--- /dev/null
+++ b/testcases/type-propagation/stringliteral.baseline.txt
@@ -0,0 +1,10 @@
+library;
+import self as self;
+
+static field dynamic/dart.core::String* {string} color = "brown";
+static field dynamic/dart.core::String* {string} thing = "lazy dog";
+static field dynamic/dart.core::String* {string} phrase = "The quick ${self::color} fox\njumped over the ${self::thing}.\n";
+static field dynamic/dart.core::String* {string} adjacent = "${self::color}${self::color}${self::color}";
+static field dynamic/dart.core::String* {string} linebreaks = "${self::color}\n${self::color}\n${self::color}";
+static field dynamic/dart.core::String* {string} other = "${self::color}\n is \n${self::color}";
+static method main() → dynamic/Null {}