debugger: assume that not-known-to-be-simple types have children

This might lead to false positives in corner cases like empty structures
but speed up the display of arrays and lists of user-defined types a lot.

src/plugins/debugger/watchhandler.cpp

@@ -180,8 +180,17 @@ void WatchData::setType(const QString &str)
             changed = false;
     }
     setTypeUnneeded();
-    if (isIntOrFloatType(type))
-        setHasChildren(false);
+    switch (guessChildren(type)) {
+        case HasChildren:
+            setHasChildren(true);
+            break;
+        case HasNoChildren:
+            setHasChildren(false);
+            break;
+        case HasPossiblyChildren:
+            setHasChildren(true); // FIXME: bold assumption
+            break;
+    }
 }
 
 void WatchData::setAddress(const QString &str)