Fix otapreopt parameters reading

The code was missing a break in the switch statement and was always
failing the default CHECK.

Also, move the logging to standard error to make it obvious the test
failed (instead of relying on the exit code which can be easily missed).

(cherry picked from commit fd0c5b1a)

Test: installd_otapreopt_test
Bug: 71993124
Merged-In: Iaf29ebc9b930981bf3b75c33e63e940139421e1d
Change-Id: Iaf29ebc9b930981bf3b75c33e63e940139421e1d