regex: Fixed spurious matches when grepping with .*

[SVN r9686]

demo/regress/tests.txt

@@ -762,6 +762,8 @@ a+ "...aaa,,," $0 aaa
 a+ "...aaa,,," $1 ""
 a+ "...aaa,,," $15 ""
 (a+)b+ "...aaabbb,,," $1 aaa
+[[:digit:]]* 123ab <$0> <123><><><>
+[[:digit:]]* 123ab1 <$0> <123><><><1>
 
 ; and now escapes:
 a+ "...aaa,,," $x "$x" 
@@ -868,3 +870,4 @@ a+(?#b+)b+ xaaabbba 1 7
 
 
 
+