strconv: add Atoi test cases with characters less than '0'

Change-Id: I35c0fe4e7e11b694ef07687d5e0532a2ab9ba213
GitHub-Last-Rev: e0a28f4
GitHub-Pull-Request: #58575
Reviewed-on: https://go-review.googlesource.com/c/go/+/469035
Auto-Submit: Robert Griesemer <[email protected]>
Run-TryBot: Robert Griesemer <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
Reviewed-by: Robert Griesemer <[email protected]>

Author: anuraaga

src/strconv/atoi_test.go

@@ -164,6 +164,7 @@ var parseInt64Tests = []parseInt64Test{
 	{"_12345", 0, ErrSyntax},
 	{"1__2345", 0, ErrSyntax},
 	{"12345_", 0, ErrSyntax},
+	{"123%45", 0, ErrSyntax},
 }
 
 type parseInt64BaseTest struct {
@@ -302,6 +303,7 @@ var parseInt32Tests = []parseInt32Test{
 	{"_12345", 0, ErrSyntax},
 	{"1__2345", 0, ErrSyntax},
 	{"12345_", 0, ErrSyntax},
+	{"123%45", 0, ErrSyntax},
 }
 
 type numErrorTest struct {