Debugger: Adjust libcpp based optional dumper

There is no added value in providing the value of the
internal 'engaged' - just provide the value if possible.

Change-Id: I8c308902bf82c43e4238568fc9b185c3a3994b47
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: David Schulz <david.schulz@qt.io>

share/qtcreator/debugger/libcpp_stdtypes.py

@@ -508,12 +508,9 @@ def qdump__std____1__variant(d, value):
 
 def qdump__std____1__optional(d, value):
     if value['__engaged_'].integer() == 0:
-        d.putSpecialValue("uninitialized")
-    d.putNumChild(2)
-    if d.isExpanded():
-        with Children(d):
-            d.putSubItem("engaged", value['__engaged_'])
-            d.putSubItem("value", value['#1']['__val_'])
+        d.putSpecialValue("empty")
+    else:
+        d.putItem(value['#1']['__val_'])
 
 
 def qdump__std____1__tuple(d, value):

share/qtcreator/debugger/stdtypes.py

@@ -1108,7 +1108,7 @@ def qdump__std__optional(d, value):
         d.putItem(payload)
         d.putBetterType(innerType)
     else:
-        d.putSpecialValue("uninitialized")
+        d.putSpecialValue("empty")
 
 
 def qdump__std__experimental__optional(d, value):

tests/auto/debugger/tst_dumpers.cpp

@@ -5627,7 +5627,7 @@ void tst_Dumpers::dumper_data()
 
                + Cxx17Profile()
 
-               + Check("o1", "<uninitialized>", "std::optional<bool>")
+               + Check("o1", "<empty>", "std::optional<bool>")
                + Check("o2", "1", "bool") // 1 -> true is done on display
                + Check("o3", "<3 items>", "std::vector<int>")
                + Check("o3.1", "[1]", "2", "int");