Added SPDX-license-identifier-Apache-2.0 to:
  Android.bp
  common/Android.bp
  java/Android.bp
  native/dicttoolkit/Android.bp
  native/jni/Android.bp
  tests/Android.bp
  tools/EditTextVariations/Android.bp
  tools/dicttool/Android.bp
  tools/make-keyboard-text/Android.bp

Bug: 68860345
Bug: 151177513
Bug: 151953481

Test: m all

Exempt-From-Owner-Approval: janitorial work
Change-Id: I440008bffac5c97a2497970af377a9d03262b6d8