Revert "Revert "Re-enable boot image string sharpening.""

The reason for the revert was a transaction bug fixed by
    https://android-review.googlesource.com/271008

Bug: 20323084
Bug: 31239436

This reverts commit f508c565.

Change-Id: I2f5995b55ccbf58b888db3f0ab64d6186e400a92