clarified system option: guard for testing, until the database layout has stabilized;

--- a/etc/options	Sun Feb 26 21:17:53 2023 +0000
+++ b/etc/options	Mon Feb 27 10:26:36 2023 +0100
@@ -183,7 +183,7 @@
 option build_engine : string = ""
   -- "alternative session build engine"
 
-option build_database : bool = false
+option build_database_test : bool = false
   -- "expose state of build process via central database"
 
 

--- a/src/Pure/Tools/build_process.scala	Sun Feb 26 21:17:53 2023 +0000
+++ b/src/Pure/Tools/build_process.scala	Mon Feb 27 10:26:36 2023 +0100
@@ -515,7 +515,7 @@
     }
 
   protected val database: Option[SQL.Database] =
-    if (!build_options.bool("build_database") || true /*FIXME*/) None
+    if (!build_options.bool("build_database_test")) None
     else if (store.database_server) Some(store.open_database_server())
     else {
       val db = SQLite.open_database(Build_Process.Data.database)