libdvm should block SIGPIPE like the RI does.

Normally AndroidRuntime.cpp patches over this lapse, but that means
that tests run by vogar or any other kind of "bare" VM doesn't handle
SIGPIPE correctly. I'll remove the workaround from AndroidRuntime.cpp.

(cherry-pick of 8723464b85290c1b348bf3e29d06e6d0a291fd4c.)

Bug: 10211309
Change-Id: I5ecb9cbb80b174590694a8837e71507b595ef6de