Add regression tests from wren-fuzz.

These are all non-crashing now, so it looks like the underlying issue
is fixed. (It was probably #429.)

Fix #442.

test/regression/442-000005.wren

@@ -0,0 +1,15 @@
+System.print("Held!")
+
+// expect error line 8
+class Wren {
+yTo(city) {
+System.print("Fl0to %(bity)")
+  }
+GGGGGGCGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGing GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG}
+
+vach GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG}
+
+vach {|word|èiberd(wryield(word) }
+}
+
+while (!ad