Add test for font crash protection.

This test modifies the installed font file with block_device_writer.
FontManagerService should detect it and remove the modified file.

Bug: 176939176
Test: atest ApkVerityTest
Test: atest UpdatableSystemFontTest
Change-Id: I7da3f2911459619d5d56a94e091b912d67cb27d3
7 files changed