[scudo][standalone] Split logs on Android

Summary:
The function used to log on Android will cut the message past
a certain amount of characters, which mostly materializes when
dumping the size class map on OOM.

This change splits the log message at newline boundaries.

Reviewers: pcc, cferris, hctim, eugenis

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D78018