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/analysis.go b/llgo/third_party/gotools/go/pointer/analysis.go
index c8e9e13..d02c3f7 100644
--- a/llgo/third_party/gotools/go/pointer/analysis.go
+++ b/llgo/third_party/gotools/go/pointer/analysis.go
@@ -255,7 +255,7 @@
 		// (This only checks that the package scope is complete,
 		// not that func bodies exist, but it's a good signal.)
 		if !pkg.Object.Complete() {
-			return nil, fmt.Errorf(`pointer analysis requires a complete program yet package %q was incomplete (set loader.Config.SourceImports during loading)`, pkg.Object.Path())
+			return nil, fmt.Errorf(`pointer analysis requires a complete program yet package %q was incomplete (don't set loader.Config.ImportFromBinary during loading)`, pkg.Object.Path())
 		}
 	}