dev: add rewritable paths for norm tests

Tests in `pkg/sql/opt/norm` are similar to tests in `pkg/sql/opt/xform`
and `pkg/sql/opt/memo` in that they rely on fixtures in
`pkg/sql/opt/testutils/opttester/testfixtures`. This commit adds these
fixtures are rewritable paths for norm tests so that
`./dev test pkg/sql/opt/xform --rewrite` does not fail with errors like:

    open pkg/sql/opt/testutils/opttester/testfixtures/tpcc_schema: operation not permitted

Release note: None

pkg/cmd/dev/test.go

@@ -128,6 +128,7 @@ func (d *dev) test(cmd *cobra.Command, commandLine []string) error {
 		extraRewritablePaths = []struct{ pkg, path string }{
 			{"pkg/ccl/logictestccl", "pkg/sql/logictest"},
 			{"pkg/sql/opt/memo", "pkg/sql/opt/testutils/opttester/testfixtures"},
+			{"pkg/sql/opt/norm", "pkg/sql/opt/testutils/opttester/testfixtures"},
 			{"pkg/sql/opt/xform", "pkg/sql/opt/testutils/opttester/testfixtures"},
 		}
 	)