Query log size properties only within logd

liblog exposed __android_logger_get_buffer_size() which queries log
size properties, but that should not be a generic library function.
Logd should be the only process that queries these properties and
other processes should query the actual used log sizes from logd via
the android_logger_get_log_*_size() functions.

Also, always use 1MB for log buffer tests, instead of just on host and
various other clean up related to improper types.

Test: log buffers are correctly sized
Merged-In: I9b7c86bf58e569618737afe9097cf1c4d4e61d95
Change-Id: I9b7c86bf58e569618737afe9097cf1c4d4e61d95