global: java access control has important semantic meaning

It's not right to blindly follow all of AndroidStudio's suggestions,
especially for things in tunnel/ which comprise useful API.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

tunnel/src/main/java/com/wireguard/android/util/ToolsInstaller.java

@@ -107,7 +107,7 @@ public final class ToolsInstaller {
         }
     }
 
-    private boolean extract() throws IOException {
+    public boolean extract() throws IOException {
         localBinaryDir.mkdirs();
         final File[] files = new File[EXECUTABLES.length];
         final File[] tempFiles = new File[EXECUTABLES.length];