Add SDK member support for cc_object.

Test: m nothing
Test: Add
    sdk {
        name: "runtime-module-sdk",
        native_shared_libs: [
            "libc",
            "libdl",
            "libm",
            "ld-android",
        ],
        native_objects: [
            "crtbegin_dynamic",
            "crtbegin_static",
            "crtend_android",
        ],
    }
  to bionic/apex/Android.bp. Then:
    build/soong/scripts/build-aml-prebuilts.sh runtime-module-sdk
  Take the generated runtime-module-sdk-current.zip and unzip into a
  master-art tree without bionic/, edit the generated Android.bp to
  extend cc_prebuilt_* modules with:
    nocrt: true,
    stl: "none",
    system_shared_libs: [],
    apex_available: ["//apex_available:anyapex"],
    recovery_available: true,
    vendor_available: true,
    ramdisk_available: true,
  Then "m com.android.art.debug". This passes Soong but fails in the
  build step because more members are required.
Bug: 148934017
Merged-In: I2ab8f6aadb1440b325697cae4a8ed761c62d15d2
Change-Id: I2ab8f6aadb1440b325697cae4a8ed761c62d15d2
(cherry picked from commit cd07bce437)

cc/library_sdk_member.go

@@ -18,6 +18,7 @@ import (
 	"path/filepath"
 
 	"android/soong/android"
+
 	"github.com/google/blueprint"
 	"github.com/google/blueprint/proptools"
 )
@@ -63,7 +64,10 @@ type librarySdkMemberType struct {
 
 	prebuiltModuleType string
 
-	// The set of link types supported, set of "static", "shared".
+	noOutputFiles bool // True if there are no srcs files.
+
+	// The set of link types supported. A set of "static", "shared", or nil to
+	// skip link type variations.
 	linkTypes []string
 }
 
@@ -337,7 +341,7 @@ func (p *nativeLibInfoProperties) PopulateFromVariant(ctx android.SdkMemberConte
 
 	// If the library has some link types then it produces an output binary file, otherwise it
 	// is header only.
-	if p.memberType.linkTypes != nil {
+	if !p.memberType.noOutputFiles {
 		p.outputFile = ccModule.OutputFile().Path()
 	}