Soong system image may update the $PRODUCT_OUT

A target must define "USE_SOONG_DEFINED_SYSTEM_IMAGE := true" and
"PRODUCT_SOONG_DEFINED_SYSTEM_IMAGE := <name of soong system image>"
to use the soong defined system image.
The system image must install the files to $PRODUCT_OUT for adb sync
and build verification. Instead of using 'update_product_out'
property in Android.bp, copy the files only if the name of the image
matches with PRODUCT_SOONG_DEFINED_SYSTEM_IMAGE.

Bug: 350599535
Bug: 365700376
Test: lunch aosp_x86_64-trunk_staging-userdebug && m &&
      m aosp_cf_system_x86_64
Test: lunch aosp_cf_x86_64_phone_soong_system-trunk_staging-userdebug
      && m
      and adb sync on the cf device
Change-Id: If8673ba2855a753a5559a588bd83068d950fd7e4

android/config.go

@@ -1663,6 +1663,17 @@ func (c *config) ApexTrimEnabled() bool {
 	return Bool(c.productVariables.TrimmedApex)
 }
 
+func (c *config) UseSoongSystemImage() bool {
+	return Bool(c.productVariables.UseSoongSystemImage)
+}
+
+func (c *config) SoongDefinedSystemImage() string {
+	if c.UseSoongSystemImage() {
+		return String(c.productVariables.ProductSoongDefinedSystemImage)
+	}
+	return ""
+}
+
 func (c *config) EnforceSystemCertificate() bool {
 	return Bool(c.productVariables.EnforceSystemCertificate)
 }