bitbake: data_smart: use the expand_cache in VariableParse

When in VariableParse, use the expand_cache if possible rather than looking
up data. Ultimately it would come from the same place but this short cuts
a heavily used code block for speed improvements.

(Bitbake rev: f682b8b83d21d576160bac8dc57c4c989b4dc555)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/data_smart.py

@@ -94,6 +94,11 @@ class VariableParse:
             if self.varname and key:
                 if self.varname == key:
                     raise Exception("variable %s references itself!" % self.varname)
+            if key in self.d.expand_cache:
+                varparse = self.d.expand_cache[key]
+                self.references |= varparse.references
+                self.execs |= varparse.execs
+                return varparse.value
             var = self.d.getVar(key, True)
             if var is not None:
                 self.references.add(key)