Add STRICMP case-insensitive string compare function (#2164)

test/asm/string-compare.asm

@@ -5,3 +5,11 @@ assert "fire flower" === "fire" ++ " " ++ "flower"
 assert "a" === "b" == 0
 assert 1 == "a" !== "b"
 assert 1 + 2 * 3 ** "x" !== "y" == 7
+
+assert !STRICMP("hello", "hello")
+assert !STRICMP("hello", "HELLO")
+assert !STRICMP("HeLlO", "hElLo")
+assert STRICMP("HELLO", "goodBYE") > 0
+assert STRICMP("hello", "GOODbye") > 0
+assert STRICMP("", "hello") < 0
+assert STRICMP("hello", "") > 0