Make asserts buildDeclared() more lenient
Declared instance is guarded by completed phase, hence if it is
filled with a value we have completed specified phase (at some point).
This results in fewer memory accesses in case the declared statement
is accessed again.
JIRA: YANGTOOLS-652
Change-Id: Iac21fb6e74268770d91e4b9eefc120b892fd0753
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>
(cherry picked from commit
e32df17e048c955ef24ef36871a078fec43a3574)
(cherry picked from commit
5d1a99d3b37029df33992a36bba41984393529e4)