Support shared_libs, static_libs and default_shared_libs in cc_object

cc_object files don't link against static or shared libraries, but they
can use headers from them.  Make cc_object use the default_shared_libs
headers, and add support for explicit static and shared library
dependencies.

Bug: 153662223
Test: go test ./cc/...
Change-Id: I9ab160ede06db1b135d217d72770c22f500cfe1b
diff --git a/cc/testing.go b/cc/testing.go
index 80cc0ef..b9d84f6 100644
--- a/cc/testing.go
+++ b/cc/testing.go
@@ -367,6 +367,7 @@
 			stl: "none",
 			min_sdk_version: "16",
 			crt: true,
+			default_shared_libs: [],
 			apex_available: [
 				"//apex_available:platform",
 				"//apex_available:anyapex",