runtime: remove rnd calls that pass a second argument of 1

When rnd is called with a second argument of 1, it simply
returns the first argument anyway.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4820045

src/pkg/runtime/chan.c

@@ -427,7 +427,7 @@ runtime·chanrecv2(Hchan* c, ...)
 
 	o = runtime·rnd(sizeof(c), Structrnd);
 	ae = (byte*)&c + o;
-	o = runtime·rnd(o+c->elemsize, 1);
+	o += c->elemsize;
 	ac = (byte*)&c + o;
 
 	runtime·chanrecv(c, ae, nil, ac);

src/pkg/runtime/hashmap.c

@@ -753,12 +753,12 @@ runtime·makemap_c(Type *key, Type *val, int64 hint)
 	// func(key) (val[, pres])
 	h->ko1 = runtime·rnd(sizeof(h), key->align);
 	h->vo1 = runtime·rnd(h->ko1+keysize, Structrnd);
-	h->po1 = runtime·rnd(h->vo1+valsize, 1);
+	h->po1 = h->vo1 + valsize;
 
 	// func(key, val[, pres])
 	h->ko2 = runtime·rnd(sizeof(h), key->align);
 	h->vo2 = runtime·rnd(h->ko2+keysize, val->align);
-	h->po2 = runtime·rnd(h->vo2+valsize, 1);
+	h->po2 = h->vo2 + valsize;
 
 	if(debug) {
 		runtime·printf("makemap: map=%p; keysize=%d; valsize=%d; keyalg=%d; valalg=%d; offsets=%d,%d; %d,%d,%d; %d,%d,%d\n",

src/pkg/runtime/iface.c

@@ -265,7 +265,7 @@ runtime·assertI2T2(Type *t, Iface i, ...)
 
 	ret = (byte*)(&i+1);
 	wid = t->size;
-	ok = (bool*)(ret+runtime·rnd(wid, 1));
+	ok = (bool*)(ret + wid);
 
 	if(i.tab == nil || i.tab->type != t) {
 		*ok = false;
@@ -327,7 +327,7 @@ runtime·assertE2T2(Type *t, Eface e, ...)
 		runtime·throw("invalid interface value");
 	ret = (byte*)(&e+1);
 	wid = t->size;
-	ok = (bool*)(ret+runtime·rnd(wid, 1));
+	ok = (bool*)(ret + wid);
 
 	if(t != e.type) {
 		*ok = false;