Remove references to libc_scudo.

As scudo is now the default native allocator, there is no need to
keep this library around.

Test: Builds and walleye boots.
Change-Id: I98e37eea78198223be6c4434891a8261d6d74e39
Merged-In: I98e37eea78198223be6c4434891a8261d6d74e39
(cherry picked from commit e5c49d54)