tests/basics/lexer: Add lexer tests for input starting with newlines.

tests/basics/lexer.py

@@ -9,6 +9,14 @@ exec("\n")
 exec("\n\n")
 exec("\r")
 exec("\r\r")
+exec("\t")
+exec("\r\n")
+exec("\nprint(1)")
+exec("\rprint(2)")
+exec("\r\nprint(3)")
+exec("\n5")
+exec("\r6")
+exec("\r\n7")
 print(eval("1"))
 print(eval("12"))
 print(eval("123"))