Variant of 43 (and 46), where we bring the disjunction out so it's no
longer embedded (but here it's still closed, unlike 46).

See also 56.

-- a.cue --
#DefA: A: "a"
#DefB: B: "b"

First: B: "b"
First: B: "b"

First: #DefA | #DefB
-- out/trim-v3 --
== a.cue
#DefA: A: "a"
#DefB: B: "b"

First: B: "b"
First: _

First: #DefA | #DefB
-- diff/-out/trim-v3<==>+out/trim --
diff old new
--- old
+++ new
@@ -2,7 +2,7 @@
 #DefA: A: "a"
 #DefB: B: "b"
 
-First: {}
-First: {}
+First: B: "b"
+First: _
 
 First: #DefA | #DefB
-- out/trim-v3-noshare --
== a.cue
#DefA: A: "a"
#DefB: B: "b"

First: B: "b"
First: _

First: #DefA | #DefB
-- diff/-out/trim-v3-noshare<==>+out/trim --
diff old new
--- old
+++ new
@@ -2,7 +2,7 @@
 #DefA: A: "a"
 #DefB: B: "b"
 
-First: {}
-First: {}
+First: B: "b"
+First: _
 
 First: #DefA | #DefB
-- out/trim --
== a.cue
#DefA: A: "a"
#DefB: B: "b"

First: {}
First: {}

First: #DefA | #DefB
