cmd/compile: call missing popdcl in various genxxx functions

Not calling popdcl doesn't have an impact on generated code but
the result is a growing (rather than empty) stack of symbols,
possibly causing more data to remain alive than necessary.

Also: minor cleanups.

Change-Id: Ic4fdbcd8843637d69ab1aa15e896a7e6339bc990
Reviewed-on: https://go-review.googlesource.com/20554
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Robert Griesemer <gri@golang.org>
diff --git a/src/cmd/compile/internal/gc/go.go b/src/cmd/compile/internal/gc/go.go
index 3d221e6..4bf7385 100644
--- a/src/cmd/compile/internal/gc/go.go
+++ b/src/cmd/compile/internal/gc/go.go
@@ -76,12 +76,13 @@
 	Pkg        *Pkg
 	Name       string // variable name
 	Def        *Node  // definition: ONAME OTYPE OPACK or OLITERAL
-	Label      *Label // corresponding label (ephemeral)
 	Block      int32  // blocknumber to catch redeclaration
 	Lastlineno int32  // last declaration for diagnostic
-	Origpkg    *Pkg   // original package for . import
-	Lsym       *obj.LSym
-	Fsym       *Sym // funcsym
+
+	Label   *Label // corresponding label (ephemeral)
+	Origpkg *Pkg   // original package for . import
+	Lsym    *obj.LSym
+	Fsym    *Sym // funcsym
 }
 
 type Label struct {