title: Renderscript broken with AndroidX?
body: <p>Since I've migrated to androidx I can't make Renderscript run. I'm getting following exception:</p>
  
  <blockquote>
    <p>2018-10-12 16:27:58.328 27195-27195/pl.qus.xenoamp2 A/zygote64:
    java_vm_ext.cc:504] JNI DETECTED ERROR IN APPLICATION: JNI
    NewGlobalRef called with pending exception
    java.lang.ClassNotFoundException: Didn't find class
    "android.support.v8.renderscript.RenderScript" on path:
    DexPathList[[zip file
    "/data/app/pl.qus.xenoamp2-xHJAddeg9oM-uGSxlvMp7A==/base.apk"],nativeLibraryDirectories=[/data/app/pl.qus.xenoamp2-xHJAddeg9oM-uGSxlvMp7A==/lib/arm64,
    /data/app/pl.qus.xenoamp2-xHJAddeg9oM-uGSxlvMp7A==/base.apk!/lib/arm64-v8a,
    /system/lib64, /system/vendor/lib64]] 2018-10-12 16:27:58.328
    27195-27195/pl.qus.xenoamp2 A/zygote64: java_vm_ext.cc:504]   at
    java.lang.Class
    dalvik.system.BaseDexClassLoader.findClass(java.lang.String)
    (BaseDexClassLoader.java:93) 2018-10-12 16:27:58.328
    27195-27195/pl.qus.xenoamp2 A/zygote64: java_vm_ext.cc:504]   at
    java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String,
    boolean) (ClassLoader.java:379) 2018-10-12 16:27:58.328
    27195-27195/pl.qus.xenoamp2 A/zygote64: java_vm_ext.cc:504]   at
    java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String)
    (ClassLoader.java:312) 2018-10-12 16:27:58.328
    27195-27195/pl.qus.xenoamp2 A/zygote64: java_vm_ext.cc:504]   at
    java.lang.String java.lang.Runtime.nativeLoad(java.lang.String,
    java.lang.ClassLoader, java.lang.String) (Runtime.java:-2) 2018-10-12
    16:27:58.328 27195-27195/pl.qus.xenoamp2 A/zygote64:
    java_vm_ext.cc:504]   at java.lang.String
    java.lang.Runtime.doLoad(java.lang.String, java.lang.ClassLoader)
    (Runtime.java:1099) 2018-10-12 16:27:58.328
    27195-27195/pl.qus.xenoamp2 A/zygote64: java_vm_ext.cc:504]   at void
    java.lang.Runtime.loadLibrary0(java.lang.ClassLoader,
    java.lang.String) (Runtime.java:1014) 2018-10-12 16:27:58.328
    27195-27195/pl.qus.xenoamp2 A/zygote64: java_vm_ext.cc:504]   at void
    java.lang.System.loadLibrary(java.lang.String) (System.java:1657)
    2018-10-12 16:27:58.328 27195-27195/pl.qus.xenoamp2 A/zygote64:
    java_vm_ext.cc:504]   at androidx.renderscript.RenderScript
    androidx.renderscript.RenderScript.internalCreate(android.content.Context,
    int, androidx.renderscript.RenderScript$ContextType, int)
    (RenderScript.java:1408) 2018-10-12 16:27:58.328
    27195-27195/pl.qus.xenoamp2 A/zygote64: java_vm_ext.cc:504]   at
    androidx.renderscript.RenderScript
    androidx.renderscript.RenderScript.create(android.content.Context,
    int, androidx.renderscript.RenderScript$ContextType, int)
    (RenderScript.java:1599) 2018-10-12 16:27:58.328
    27195-27195/pl.qus.xenoamp2 A/zygote64: java_vm_ext.cc:504]   at
    androidx.renderscript.RenderScript
    androidx.renderscript.RenderScript.create(android.content.Context,
    androidx.renderscript.RenderScript$ContextType, int)
    (RenderScript.java:1549) 2018-10-12 16:27:58.328
    27195-27195/pl.qus.xenoamp2 A/zygote64: java_vm_ext.cc:504]   at
    androidx.renderscript.RenderScript
    androidx.renderscript.RenderScript.create(android.content.Context,
    androidx.renderscript.RenderScript$ContextType)
    (RenderScript.java:1525) 2018-10-12 16:27:58.328
    27195-27195/pl.qus.xenoamp2 A/zygote64: java_vm_ext.cc:504]   at
    androidx.renderscript.RenderScript
    androidx.renderscript.RenderScript.create(android.content.Context)
    (RenderScript.java:1512)</p>
  </blockquote>
  
  <p>I have usual entries in gradle:</p>
  
  <pre><code>    renderscriptTargetApi 18
      renderscriptSupportModeEnabled true
  </code></pre>
  
  <p>Anything else I have to change?</p>