Roll gotools to d4e70101.

Most importantly, this gives us https://go-review.googlesource.com/7533 which
fixes a bug in go/ssa that caused test failures in the Go 1.4 standard library.

Also remove the go1.4 tag workaround. We no longer need it now that we
ship llgo-go.

Differential Revision: http://reviews.llvm.org/D8827

llvm-svn: 234133
diff --git a/llgo/third_party/gotools/go/pointer/gen.go b/llgo/third_party/gotools/go/pointer/gen.go
index 8cb3e0d..5099448 100644
--- a/llgo/third_party/gotools/go/pointer/gen.go
+++ b/llgo/third_party/gotools/go/pointer/gen.go
@@ -1262,7 +1262,7 @@
 
 	// Create nodes and constraints for all methods of all types
 	// that are dynamically accessible via reflection or interfaces.
-	for _, T := range a.prog.TypesWithMethodSets() {
+	for _, T := range a.prog.RuntimeTypes() {
 		a.genMethodsOf(T)
 	}