[CT] Add ability to run unlanded benchmarks on Chromium Perf

ct/go/db/db.go

 package db
 
 /*
         Store/Retrieve Cluster Telemetry Frontend data in a database.
 */
 
 import (
         "github.com/jmoiron/sqlx"
         "go.skia.org/infra/go/database"
 )
@@ skipping 231 matching lines @@
 }
 
 var v10_up = []string{
         `ALTER TABLE ChromiumPerfTasks CONVERT TO CHARACTER SET utf32`,
 }
 
 var v10_down = []string{
         `ALTER TABLE ChromiumPerfTasks CONVERT TO CHARACTER SET utf8`,
 }
 
+var v11_up = []string{
+        `ALTER TABLE ChromiumPerfTasks ADD benchmark_patch longtext NOT NULL DEFAULT ""`,
+}
+
+var v11_down = []string{
+        `ALTER TABLE ChromiumPerfTasks DROP benchmark_patch`,
+}
+
 // Define the migration steps.
 // Note: Only add to this list, once a step has landed in version control it
 // must not be changed.
 var migrationSteps = []database.MigrationStep{
         // version 1. Create Chromium Perf tables.
         {
                 MySQLUp:   v1_up,
                 MySQLDown: v1_down,
         },
         // version 2. Create Admin Task tables.
@@ skipping 34 matching lines @@
         // version 9: Change chromium_patch, blink_patch and skia_patch to longtext in ChromiumPerfTasks table.
         {
                 MySQLUp:   v9_up,
                 MySQLDown: v9_down,
         },
         // version 10: Convert character set in ChromiumPerfTasks from utf8 to utf32.
         {
                 MySQLUp:   v10_up,
                 MySQLDown: v10_down,
         },
+        // version 11: Add benchmark_patch column to ChromiumPerfTasks.
+        {
+                MySQLUp:   v11_up,
+                MySQLDown: v11_down,
+        },
 }
 
 // MigrationSteps returns the database migration steps.
 func MigrationSteps() []database.MigrationStep {
         return migrationSteps
 }