Move some gob helpers to a new package.

Bug: 358427516
Test: CI
Change-Id: Ib25bbfb6e89c35cf4a080e2baaffadabf0e5636e
diff --git a/android/packaging.go b/android/packaging.go
index fe76bfc..acafcd4 100644
--- a/android/packaging.go
+++ b/android/packaging.go
@@ -21,6 +21,7 @@
 	"strings"
 
 	"github.com/google/blueprint"
+	"github.com/google/blueprint/gobtools"
 	"github.com/google/blueprint/proptools"
 )
 
@@ -109,11 +110,11 @@
 }
 
 func (p *PackagingSpec) GobEncode() ([]byte, error) {
-	return blueprint.CustomGobEncode[packagingSpecGob](p)
+	return gobtools.CustomGobEncode[packagingSpecGob](p)
 }
 
 func (p *PackagingSpec) GobDecode(data []byte) error {
-	return blueprint.CustomGobDecode[packagingSpecGob](data, p)
+	return gobtools.CustomGobDecode[packagingSpecGob](data, p)
 }
 
 func (p *PackagingSpec) Equals(other *PackagingSpec) bool {