Move globbing to Blueprint

Move Soong's globbing-with-dependencies support into Blueprint so it can
be used for subdirs= lines in Android.bp files.

Blueprint has a slight change in behavior around subname= lines, it now
always uses the subname and doesn't fall back to Blueprints.  To support
the Blueprints files in build/blueprint, use them directly with build=.

Test: build, add source file that matches glob, rebuild
Change-Id: Ifd0b0d3bc061aae0a16d6c7ca9a1cd8672656b4d
diff --git a/root.bp b/root.bp
index d82e09d..76e7aee 100644
--- a/root.bp
+++ b/root.bp
@@ -1,7 +1,10 @@
 subname = "Android.bp"
 
+build = [
+    "build/blueprint/Blueprints",
+]
+
 subdirs = [
-    "build/blueprint",
     "build/soong",
 ]