Revert^2 "Change default dalvik.vm.jdwp-provider to adbconnection"

We modified adbconnection to not load the jdwp agent until it hits
non-DDMS packets. This ensures that using DDMS enabled tools with
userdebug builds will no longer cause unacceptable slowdowns due to
loading the debugger on system_server and other system processes

This reverts commit 4650d4a3.

Reason for revert: Issue with ddms and userdebug builds has been
                   resolved.

Test: Start up userdebug device while ddms monitor is running.

Test: ./test.py --host -j50
Test: ./art/tools/run-libjdwp-tests.sh --mode=device
Test: Build and run
Test: use ddms monitor.
Test: Use Android Studio.
Test: Build and debug debuggable app (bandhook-kotlin)
Test: Build and debug non-debuggable app on userdebug build
      (bandhook-kotlin)
Test: Debug running system process on userdebug build
      (com.android.packageinstaller)
Test: adb shell stop &&
      adb shell setprop dalvik.vm.jdwp-provider adbconnection &&
      adb shell start;
      Test debugger with explicit adbconnection jdwp provider set
Test: adb shell stop &&
      adb shell setprop dalvik.vm.jdwp-provider default &&
      adb shell start;
      Test debugger with explicit default jdwp provider set
      Ensure debugger is using the 'adbconnection' provider
Test: adb shell stop &&
      adb shell setprop dalvik.vm.jdwp-provider internal &&
      adb shell start;
      Test debugger with explicit internal jdwp provider set
      Ensure debugger is using the old internal jdwp implementation.

Bug: 62821960
Change-Id: I6d1231e56a0891cb8fd2acfd6f2413d87128fbb5