Start using blueprint_go_binary

And install the tools into a more obvious location. soong_env is not
moved, since we need it to exist early, so that we can use it in
soong.bash in case there's a build failure.

Change-Id: I9bd1fa320d84d180b2cf3deb90782d380666f7a6
diff --git a/android/config.go b/android/config.go
index 8701960..ee95d2e 100644
--- a/android/config.go
+++ b/android/config.go
@@ -197,6 +197,10 @@
 	return false
 }
 
+func (c *config) BlueprintToolLocation() string {
+	return filepath.Join(c.buildDir, "host", c.PrebuiltOS(), "bin")
+}
+
 // PrebuiltOS returns the name of the host OS used in prebuilts directories
 func (c *config) PrebuiltOS() string {
 	switch runtime.GOOS {