test: add test cases for NOT NULL columns

Author: yoRyuuuuu

internal/endtoend/testdata/emit_pointers_for_null_types/mysql/go/models.go

@@ -7,6 +7,15 @@ CREATE TABLE dt_integer (
     f bigint
 );
 
+CREATE TABLE dt_integer_not_null (
+    a tinyint not null,
+    b smallint not null,
+    c int not null,
+    d integer not null,
+    e mediumint not null,
+    f bigint not null
+);
+
 CREATE TABLE dt_unsigned_integer (
     a tinyint unsigned,
     b smallint unsigned,
@@ -15,3 +24,13 @@ CREATE TABLE dt_unsigned_integer (
     e mediumint unsigned,
     f bigint unsigned
 );
+
+
+CREATE TABLE dt_unsigned_integer_not_null (
+    a tinyint unsigned not null,
+    b smallint unsigned not null,
+    c int unsigned not null,
+    d integer unsigned not null,
+    e mediumint unsigned not null,
+    f bigint unsigned not null
+);