Remove redundant float/double auto_increment tests from insert_queries.go

- Removed "auto increment on float" and "auto increment on double" tests
- These scenarios are now impossible since CREATE TABLE fails for float/double AUTO_INCREMENT
- Validation is already covered in script_queries.go tests
- Eliminates duplicate test coverage for the same validation logic

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: elianddb

enginetest/queries/insert_queries.go

@@ -1285,28 +1285,6 @@ var InsertScripts = []ScriptTest{
 			},
 		},
 	},
-	{
-		Name:    "auto increment on float",
-		Dialect: "mysql",
-		SetUpScript: []string{},
-		Assertions: []ScriptTestAssertion{
-			{
-				Query:          "create table auto (pk float primary key auto_increment)",
-				ExpectedErrStr: "Incorrect column specifier for column 'pk'",
-			},
-		},
-	},
-	{
-		Name:    "auto increment on double",
-		Dialect: "mysql",
-		SetUpScript: []string{},
-		Assertions: []ScriptTestAssertion{
-			{
-				Query:          "create table auto (pk double primary key auto_increment)",
-				ExpectedErrStr: "Incorrect column specifier for column 'pk'",
-			},
-		},
-	},
 	{
 		Name:    "sql_mode=NO_auto_value_ON_ZERO",
 		Dialect: "mysql",