Move check partition size logs to a file

Don't contaminate the build log.
Test: m check-all-partition-sizes -j (verbose logs stored to file)
Test: m check-all-partition-sizes-nodeps -j (see verbose logs)
Test: manually run the script with[out] -v and with[out] --logfile

Change-Id: I345a340deab3e29bb9cb05d4970a55d8758607a7