Fix error prone build of WM tests in FrameworksServicesTests

An erroprone build is usually triggered by Presubmit-Ready and built by
TreeHugger. You may see some failures in Presubmit Build Status of the
Gerrit. The error messages contains nice explanations and the links to how
to fix these.

Bug: 113800711
Test: Trigger Presubmit-Ready in TreeHugger and see errorprone build
  successfully.
Test: Pass all WM presubmit tests in FrameworksServicesTests and WmTests
  $ tradefed.sh run commandAndExit FrameworksServicesTests \
      --include-filter com.android.server.wm. \
      --include-annotation android.platform.test.annotations.Presubmit \
      --exclude-annotation androidx.test.filters.FlakyTest
  $ tradefed.sh run commandAndExit WmTests \
      --include-filter com.android.server.wm. \
      --include-annotation android.platform.test.annotations.Presubmit \
      --exclude-annotation androidx.test.filters.FlakyTest
Change-Id: I06c8162d4196346c4e90557e75f29088f5917284