Globally allow up to 32K FDs open per process

We've seen crashes due to processes exceeding the current soft limit
for open FDs of 1024, mainly due to increases in using FDs for shared
memory and gralloc memory objects.

There is not a compelling reason to keep this limit artificially low,
so we raise it to 32K.  This matches my desktop linux limit, so it is
with precedent.

Bug: 64894637
Test: open 32K FDs in a process without failure then fail after 32K
Change-Id: Ibecfc486e9c61f273a432a108893137d2d13a530