adbd: improve thread names.

Name each service thread specifically to improve debuggability.

Bug: http://b/65648324
Bug: 64709603 (presubmit balking at the line above)
Test: adb shell debuggerd -b `adb shell pidof adbd` during a sync
Change-Id: I644e25fc2f14a26eafd19f596e4e8f3c2bb79967
(cherry picked from commit bcadc775)