Revert "Multithread symlink forest removal."

This reverts commit 6b236f1607e4a039700a287ff2368e02f583d6fd.

Reason for revert: Breaks ab/aosp-master-bazel incremental builds. Details on b/254338319

Change-Id: I37eeeda50cff0475d91e7926fdf74216975a0037
diff --git a/bp2build/java_binary_host_conversion_test.go b/bp2build/java_binary_host_conversion_test.go
index 8000477..86f3d42 100644
--- a/bp2build/java_binary_host_conversion_test.go
+++ b/bp2build/java_binary_host_conversion_test.go
@@ -32,7 +32,7 @@
 	}, tc)
 }
 
-var testFs = map[string]string{
+var fs = map[string]string{
 	"test.mf": "Main-Class: com.android.test.MainClass",
 	"other/Android.bp": `cc_library_host_shared {
     name: "jni-lib-1",
@@ -43,7 +43,7 @@
 func TestJavaBinaryHost(t *testing.T) {
 	runJavaBinaryHostTestCase(t, Bp2buildTestCase{
 		Description: "java_binary_host with srcs, exclude_srcs, jni_libs, javacflags, and manifest.",
-		Filesystem:  testFs,
+		Filesystem:  fs,
 		Blueprint: `java_binary_host {
     name: "java-binary-host-1",
     srcs: ["a.java", "b.java"],
@@ -76,7 +76,7 @@
 func TestJavaBinaryHostRuntimeDeps(t *testing.T) {
 	runJavaBinaryHostTestCase(t, Bp2buildTestCase{
 		Description: "java_binary_host with srcs, exclude_srcs, jni_libs, javacflags, and manifest.",
-		Filesystem:  testFs,
+		Filesystem:  fs,
 		Blueprint: `java_binary_host {
     name: "java-binary-host-1",
     static_libs: ["java-dep-1"],
diff --git a/bp2build/symlink_forest.go b/bp2build/symlink_forest.go
index 0fa9c50..45817e3 100644
--- a/bp2build/symlink_forest.go
+++ b/bp2build/symlink_forest.go
@@ -15,9 +15,7 @@
 package bp2build
 
 import (
-	"errors"
 	"fmt"
-	"io/fs"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -319,45 +317,6 @@
 	}
 }
 
-func removeParallelRecursive(path string, fi os.FileInfo, wg *sync.WaitGroup) {
-	defer wg.Done()
-
-	if fi.IsDir() {
-		children := readdirToMap(path)
-		childrenWg := &sync.WaitGroup{}
-		childrenWg.Add(len(children))
-
-		for child, childFi := range children {
-			go removeParallelRecursive(shared.JoinPath(path, child), childFi, childrenWg)
-		}
-
-		childrenWg.Wait()
-	}
-
-	if err := os.Remove(path); err != nil {
-		fmt.Fprintf(os.Stderr, "Cannot unlink '%s': %s\n", path, err)
-		os.Exit(1)
-	}
-}
-
-func removeParallel(path string) {
-	fi, err := os.Lstat(path)
-	if err != nil {
-		if errors.Is(err, fs.ErrNotExist) {
-			return
-		}
-
-		fmt.Fprintf(os.Stderr, "Cannot lstat '%s': %s\n", path, err)
-		os.Exit(1)
-	}
-
-	wg := &sync.WaitGroup{}
-	wg.Add(1)
-	removeParallelRecursive(path, fi, wg)
-
-	wg.Wait()
-}
-
 // Creates a symlink forest by merging the directory tree at "buildFiles" and
 // "srcDir" while excluding paths listed in "exclude". Returns the set of paths
 // under srcDir on which readdir() had to be called to produce the symlink
@@ -371,7 +330,7 @@
 
 	context.okay.Store(true)
 
-	removeParallel(shared.JoinPath(topdir, forest))
+	os.RemoveAll(shared.JoinPath(topdir, forest))
 
 	instructions := instructionsFromExcludePathList(exclude)
 	go func() {