chore: fix concurrent CommitQuota transactions for unrelated users/orgs (#15261)

The failure condition being fixed is `w1` and `w2` could belong
to different users, organizations, and templates and still cause a
serializable failure if run concurrently. This is because the old query 
did a `seq scan` on the `workspace_builds` table. Since that is the 
table being updated, we really want to prevent that.

So before this would fail for any 2 workspaces. Now it only fails if
`w1` and `w2` are owned by the same user and organization.

coderd/database/dbfake/builder.go

@@ -0,0 +1,127 @@
+package dbfake
+
+import (
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+
+	"github.com/coder/coder/v2/coderd/database"
+	"github.com/coder/coder/v2/coderd/database/dbauthz"
+	"github.com/coder/coder/v2/coderd/database/dbgen"
+	"github.com/coder/coder/v2/coderd/database/dbtime"
+	"github.com/coder/coder/v2/testutil"
+)
+
+type OrganizationBuilder struct {
+	t                 *testing.T
+	db                database.Store
+	seed              database.Organization
+	allUsersAllowance int32
+	members           []uuid.UUID
+	groups            map[database.Group][]uuid.UUID
+}
+
+func Organization(t *testing.T, db database.Store) OrganizationBuilder {
+	return OrganizationBuilder{
+		t:       t,
+		db:      db,
+		members: []uuid.UUID{},
+		groups:  make(map[database.Group][]uuid.UUID),
+	}
+}
+
+type OrganizationResponse struct {
+	Org           database.Organization
+	AllUsersGroup database.Group
+	Members       []database.OrganizationMember
+	Groups        []database.Group
+}
+
+func (b OrganizationBuilder) EveryoneAllowance(allowance int) OrganizationBuilder {
+	//nolint: revive // returns modified struct
+	b.allUsersAllowance = int32(allowance)
+	return b
+}
+
+func (b OrganizationBuilder) Seed(seed database.Organization) OrganizationBuilder {
+	//nolint: revive // returns modified struct
+	b.seed = seed
+	return b
+}
+
+func (b OrganizationBuilder) Members(users ...database.User) OrganizationBuilder {
+	for _, u := range users {
+		//nolint: revive // returns modified struct
+		b.members = append(b.members, u.ID)
+	}
+	return b
+}
+
+func (b OrganizationBuilder) Group(seed database.Group, members ...database.User) OrganizationBuilder {
+	//nolint: revive // returns modified struct
+	b.groups[seed] = []uuid.UUID{}
+	for _, u := range members {
+		//nolint: revive // returns modified struct
+		b.groups[seed] = append(b.groups[seed], u.ID)
+	}
+	return b
+}
+
+func (b OrganizationBuilder) Do() OrganizationResponse {
+	org := dbgen.Organization(b.t, b.db, b.seed)
+
+	ctx := testutil.Context(b.t, testutil.WaitShort)
+	//nolint:gocritic // builder code needs perms
+	ctx = dbauthz.AsSystemRestricted(ctx)
+	everyone, err := b.db.InsertAllUsersGroup(ctx, org.ID)
+	require.NoError(b.t, err)
+
+	if b.allUsersAllowance > 0 {
+		everyone, err = b.db.UpdateGroupByID(ctx, database.UpdateGroupByIDParams{
+			Name:           everyone.Name,
+			DisplayName:    everyone.DisplayName,
+			AvatarURL:      everyone.AvatarURL,
+			QuotaAllowance: b.allUsersAllowance,
+			ID:             everyone.ID,
+		})
+		require.NoError(b.t, err)
+	}
+
+	members := make([]database.OrganizationMember, 0)
+	if len(b.members) > 0 {
+		for _, u := range b.members {
+			newMem := dbgen.OrganizationMember(b.t, b.db, database.OrganizationMember{
+				UserID:         u,
+				OrganizationID: org.ID,
+				CreatedAt:      dbtime.Now(),
+				UpdatedAt:      dbtime.Now(),
+				Roles:          nil,
+			})
+			members = append(members, newMem)
+		}
+	}
+
+	groups := make([]database.Group, 0)
+	if len(b.groups) > 0 {
+		for g, users := range b.groups {
+			g.OrganizationID = org.ID
+			group := dbgen.Group(b.t, b.db, g)
+			groups = append(groups, group)
+
+			for _, u := range users {
+				dbgen.GroupMember(b.t, b.db, database.GroupMemberTable{
+					UserID:  u,
+					GroupID: group.ID,
+				})
+			}
+		}
+	}
+
+	return OrganizationResponse{
+		Org:           org,
+		AllUsersGroup: everyone,
+		Members:       members,
+		Groups:        groups,
+	}
+}