Add private dirty image section breakdown

Print how many private dirty pages there are for each image section.

Example output:

Image sections (total private dirty pages 157)
SectionObjects size=1997864 range=0-1997864 private dirty pages=53
SectionArtFields size=494988 range=1997864-2492852 private dirty pages=0
SectionArtMethods size=1397120 range=2492852-3889972 private dirty pages=29
SectionRuntimeMethods size=37824 range=4076856-4114680 private dirty pages=1
SectionImTables size=149468 range=3889972-4039440 private dirty pages=0
SectionIMTConflictTables size=37416 range=4039440-4076856 private dirty pages=0
SectionDexCacheArrays size=556680 range=4114680-4671360 private dirty pages=74
SectionInternedStrings size=200940 range=4671360-4872300 private dirty pages=0
SectionClassTable size=21468 range=4872304-4893772 private dirty pages=0
SectionImageBitmap size=32768 range=4894720-4927488 private dirty pages=0

Bug: 62554875
Test: test-art-target-imgdiag_test

Change-Id: I555c6bac8eb96d09beb110ec36eaa341163f4a1e