Revert "Filesystem modules follow the installation semantic"

Revert submission 3066748-duplicate_entry_fs

Reason for revert: b/338159248

Reverted changes: /q/submissionid:3066748-duplicate_entry_fs

Change-Id: I8aacdb36efce8343c3713542eee209e71bde660b
diff --git a/filesystem/filesystem.go b/filesystem/filesystem.go
index 5bcfce7..cadf9c2 100644
--- a/filesystem/filesystem.go
+++ b/filesystem/filesystem.go
@@ -137,7 +137,6 @@
 // partitions like system.img. For example, cc_library modules are placed under ./lib[64] directory.
 func filesystemFactory() android.Module {
 	module := &filesystem{}
-	module.filterPackagingSpec = module.filterInstallablePackagingSpec
 	initFilesystemModule(module)
 	return module
 }
@@ -190,12 +189,6 @@
 	return proptools.StringDefault(f.properties.Partition_name, f.Name())
 }
 
-func (f *filesystem) filterInstallablePackagingSpec(ps android.PackagingSpec) bool {
-	// Filesystem module respects the installation semantic. A PackagingSpec from a module with
-	// IsSkipInstall() is skipped.
-	return !ps.SkipInstall()
-}
-
 var pctx = android.NewPackageContext("android/soong/filesystem")
 
 func (f *filesystem) GenerateAndroidBuildActions(ctx android.ModuleContext) {
diff --git a/filesystem/system_image.go b/filesystem/system_image.go
index 15cacfb..5028a49 100644
--- a/filesystem/system_image.go
+++ b/filesystem/system_image.go
@@ -98,5 +98,5 @@
 // Note that "apex" module installs its contents to "apex"(fake partition) as well
 // for symbol lookup by imitating "activated" paths.
 func (s *systemImage) filterPackagingSpec(ps android.PackagingSpec) bool {
-	return s.filesystem.filterInstallablePackagingSpec(ps) && ps.Partition() == "system"
+	return ps.Partition() == "system"
 }