Add overrides support for snapshots

Overrides properties will now be captured in json flag files, which will
be copied to installed vendor snapshot modules.

Bug: 216567575
Test: soong test && manual install
Change-Id: Ife5e84b126e798fba7802b9cff000c9197756cb9

cc/binary.go

@@ -540,6 +540,12 @@ func (binary *binaryDecorator) hostToolPath() android.OptionalPath {
 	return binary.toolPath
 }
 
+func (binary *binaryDecorator) overriddenModules() []string {
+	return binary.Properties.Overrides
+}
+
+var _ overridable = (*binaryDecorator)(nil)
+
 func init() {
 	pctx.HostBinToolVariable("verifyHostBionicCmd", "host_bionic_verify")
 }