[dev.ssa] test: remove extra tests from non-SSA builds

non-SSA backends are all over the map as to whether nil checks
get removed or not.  amd64, 386, 386/387, arm are all subtly different.
Remove these extra checks for now, they are in nilptr3_ssa.go so they
won't get lost.

Change-Id: I2e0051f488fb2cb7278c6fdd44cb9d68b5778345
Reviewed-on: https://go-review.googlesource.com/19961Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

test/nilptr3.go

@@ -193,21 +193,3 @@ func f4(x *[10]int) {
 	x = y
 	_ = &x[9] // ERROR "removed repeated nil check"
 }
-
-func f5(p *float32, q *float64, r *float32, s *float64) float64 {
-	x := float64(*p) // ERROR "removed nil check"
-	y := *q          // ERROR "removed nil check"
-	*r = 7           // ERROR "removed nil check"
-	*s = 9           // ERROR "removed nil check"
-	return x + y
-}
-
-type T [29]byte
-
-func f6(p, q *T) {
-	x := *p // ERROR "generated nil check"
-	// On ARM, the nil check on this store gets removed.  On other archs,
-	// it doesn't.  Makes this hard to test.  SSA will always remove it.
-	//*q = x
-	_ = x
-}