cmd/5g etc: merge simple case expressions onto fewer lines

The c2go translation left a lot of case expressions on separate lines.
Merge expressions onto single lines subject to these constraints:

* Max 4 clauses, all literals or names
* Don't move expressions with comments

The change was created by running http://play.golang.org/p/yHajs72h-g:

$ mergecase cmd/internal/{ld,gc,obj}/*.go cmd/internal/obj/*/*.go

Passes toolstash -cmp.

Change-Id: Iba41b390d302e5486e5dc6ba7599a92270676556
Reviewed-on: https://go-review.googlesource.com/7593
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
diff --git a/src/cmd/internal/gc/reflect.go b/src/cmd/internal/gc/reflect.go
index 35984f1..bd5be0f 100644
--- a/src/cmd/internal/gc/reflect.go
+++ b/src/cmd/internal/gc/reflect.go
@@ -1148,8 +1148,7 @@
 		ot = duint16(s, ot, uint16(mapbucket(t).Width))
 		ot = duint8(s, ot, uint8(bool2int(isreflexive(t.Down))))
 
-	case TPTR32,
-		TPTR64:
+	case TPTR32, TPTR64:
 		if t.Type.Etype == TANY {
 			// ../../runtime/type.go:/UnsafePointerType
 			ot = dcommontype(s, ot, t)
@@ -1213,9 +1212,7 @@
 	// we want be able to find.
 	if t.Sym == nil {
 		switch t.Etype {
-		case TARRAY,
-			TCHAN,
-			TMAP:
+		case TARRAY, TCHAN, TMAP:
 			slink := typelinksym(t)
 			dsymptr(slink, 0, s, 0)
 			ggloblsym(slink, int32(Widthptr), int8(dupok|obj.RODATA))