Get underline position and thickness from the font

Previously, font underline position and thickness were fixed in Android.
Although a custom font may have specified a different value, such a value
would never be used. Now we use the values from the font if they are
provided and fall back to the old default values only if needed.

Bug: 62353930

Test: adb shell am instrument -w -e package android.graphics com.android.frameworks.coretests/android.support.test.runner.AndroidJUnitRunner
Test: adb shell am instrument -w -e package android.text com.android.frameworks.coretests/android.support.test.runner.AndroidJUnitRunner
Test: cts-tradefed run cts-dev --module CtsTextTestCases
Test: Manual
Change-Id: I6bf21000dd69a2780c894b231638bc0c122e41f4