Added LoadDefaultSchema to platform testing utils to make test setup easier. (#38706)

<!-- Add the related story/sub-task/bug number, like Resolves #123, or
remove if NA -->
**Related issue:** Resolves #38234

Minor developer experience improvement for tests using MySQL.
This is a code review follow up.

server/activity/internal/testutils/testutils.go

@@ -3,8 +3,6 @@ package testutils
 
 import (
 	"encoding/json"
-	"path/filepath"
-	"runtime"
 	"testing"
 	"time"
 
@@ -29,10 +27,7 @@ func SetupTestDB(t *testing.T, testNamePrefix string) *TestDB {
 		UniqueTestName: testNamePrefix + "_" + t.Name(),
 	})
 
-	_, thisFile, _, _ := runtime.Caller(0)
-	schemaPath := filepath.Join(filepath.Dir(thisFile), "../../../../server/datastore/mysql/schema.sql")
-	mysql_testing_utils.LoadSchema(t, testName, opts, schemaPath)
-
+	mysql_testing_utils.LoadDefaultSchema(t, testName, opts)
 	config := mysql_testing_utils.MysqlTestConfig(testName)
 	db, err := common_mysql.NewDB(config, &common_mysql.DBOptions{}, "")
 	require.NoError(t, err)

server/datastore/mysql/testing_utils.go

@@ -15,9 +15,7 @@ import (
 	"io"
 	"os"
 	"os/exec"
-	"path"
 	"regexp"
-	"runtime"
 	"strconv"
 	"strings"
 	"sync"
@@ -366,9 +364,7 @@ func setupRealReplica(t testing.TB, testName string, ds *Datastore, options *com
 // MySQL. This is much faster than running the full set of migrations on each
 // test.
 func initializeDatabase(t testing.TB, testName string, opts *testing_utils.DatastoreTestOptions) *Datastore {
-	_, filename, _, _ := runtime.Caller(0)
-	schemaPath := path.Join(path.Dir(filename), "schema.sql")
-	testing_utils.LoadSchema(t, testName, opts, schemaPath)
+	testing_utils.LoadDefaultSchema(t, testName, opts)
 	return connectMySQL(t, testName, opts)
 }
 

server/platform/mysql/testing_utils/testing_utils.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"runtime"
 	"strings"
 	"testing"
@@ -107,6 +108,14 @@ type DatastoreTestOptions struct {
 	UniqueTestName string
 }
 
+// LoadDefaultSchema loads the default database schema for testing.
+func LoadDefaultSchema(t testing.TB, testName string, opts *DatastoreTestOptions) {
+	_, thisFile, _, _ := runtime.Caller(0)
+	schemaPath := filepath.Join(filepath.Dir(thisFile), "../../../datastore/mysql/schema.sql")
+	LoadSchema(t, testName, opts, schemaPath)
+}
+
+// LoadSchema loads a database schema from the specified path for testing.
 func LoadSchema(t testing.TB, testName string, opts *DatastoreTestOptions, schemaPath string) {
 	schema, err := os.ReadFile(schemaPath)
 	if err != nil {