Change scheduling preference for EraVM

[vladimirradosavljevic]

Currently, default scheduling preference is used for EraVM. Try to find a better scheduling preference that can give more improvements.
#678 was an experiment to set it to RegPressure, but there were regressions in __clz and __mulmod functions. This was because instructions were scheduled differently and some BE optimization weren't able to optimize code. Maybe one way to fix this is to try to change implementation of __clz function, but that is something to investigate.