Fix art_imgdiag_tests

Don't check that zygote/image pagemap files are different, because they
refer to the same file in ImgDiagTest.ImageDiffPidSelf.

Test: art/tools/run-gtests.sh /apex/com.android.art/bin/art/x86/art_imgdiag_tests
Change-Id: Ife65683f7b6953a2c830d5f88871e6899b07c421
1 file changed