dexdiag: Replace libpagemap with libmeminfo

libpagemap is to be deleted, so remove the libpagemap usage and use
libmeminfo instead.

Bug: 111694435
Test: dexdiag `pidof com.google.android.calendar`

Change-Id: I4ecb1c56bf5f4ac518e3c51a392591a4a3f0b2fb
Signed-off-by: Sandeep Patil <sspatil@google.com>