Fix umm_blocks() (#8429)
Fix umm_blocks() (#8429)

Extracted fix from upstream for umm_blocks() - On allocations that were too
large, umm_blocks() could return an incorrectly truncated value when the result
is cast to uint16_t.
sticilface/Arduino,esp8266/Arduino,esp8266/Arduino,esp8266/Arduino,sticilface/Arduino,sticilface/Arduino,sticilface/Arduino,esp8266/Arduino,esp8266/Arduino,sticilface/Arduino