Add some more ignorecase tests

Author: samcv

t/qregex/rx_modifiers

@@ -1,5 +1,9 @@
 ##  modifiers
 :i st			st	y	ignorecase with ligature st (:i)
+:i st			ST	y	ignorecase with ligature st (:i)
+:i st			St	y	ignorecase with ligature st (:i)
+:i st			sT	y	ignorecase with ligature st (:i)
+:i st			st	y	reversed haystack and needle ignorecase with ligature st (:i)
 :i bcd			abcdef	y	ignorecase (:i)
 :i bcd			aBcdef	y	ignorecase (:i)
 :i bcd			abCdef	y	ignorecase (:i)