Partially revert "cache push on any thread"

This partially reverts commit 8a6b5e4
to restore `Node.cached` field.

Author: acmorrow

SCons/Node/NodeTests.py

@@ -1296,13 +1296,15 @@ def test_clear(self) -> None:
         n.includes = 'testincludes'
         n.Tag('found_includes', {'testkey':'testvalue'})
         n.implicit = 'testimplicit'
+        n.cached = 1
 
         x = MyExecutor()
         n.set_executor(x)
 
         n.clear()
 
         assert n.includes is None, n.includes
+        assert n.cached == 0, n.cached
         assert x.cleaned_up
 
     def test_get_subst_proxy(self) -> None:

SCons/Node/__init__.py

@@ -588,6 +588,7 @@ def __init__(self) -> None:
         self.pseudo = False
         self.noclean = 0
         self.nocache = 0
+        self.cached = 0 # is this node pulled from cache?
         self.always_build = None
         self.includes = None
         self.attributes = self.Attrs() # Generic place to stick information about the Node.
@@ -863,6 +864,7 @@ def clear(self) -> None:
                 delattr(self, attr)
             except AttributeError:
                 pass
+        self.cached = 0
         self.includes = None
 
     def clear_memoized_values(self) -> None:

SCons/Taskmaster/__init__.py

@@ -246,6 +246,9 @@ def execute(self):
                 self.targets[0].build()
                 for t in self.targets:
                     t.push_to_cache()
+            else:
+                for t in cached_targets:
+                    t.cached = 1
         except SystemExit:
             exc_value = sys.exc_info()[1]
             raise SCons.Errors.ExplicitExit(self.targets[0], exc_value.code)