Remove four libcxx known failures now that mkstemp/get_temp_file_name works.

An update on four libcxx known failures now that mkstemp/get_temp_file_name works.

make: *** [check-libcxx] Error 2
4773 tests, 71 failures
Parsed /mnt/data/b/build/slave/nacl-toolchain/build/native_client/pnacl/scripts/libcxx_known_failures.txt: now 75 total excludes
libc++::input.output/file.streams/fstreams/fstream.assign/member_swap.pass.cpp: unexpected success
libc++::input.output/file.streams/fstreams/ofstream.assign/member_swap.pass.cpp: unexpected success
libc++::input.output/file.streams/fstreams/fstream.assign/nonmember_swap.pass.cpp: unexpected success
libc++::input.output/file.streams/fstreams/ofstream.assign/nonmember_swap.pass.cpp: unexpected success
0 unexpected failures 4 unexpected passes

BUG=none (red FYI bot).
R=jfb@chromium.org

Committed: https://chromium.googlesource.com/native_client/src/native_client/+/d88fa4fed707a60fd29ef9d382ca030818d115a1

[jvoung (off chromium), 2015-04-16 15:51:07]

jvoung@chromium.org changed reviewers:
+ dschuff@chromium.org

[JF, 2015-04-16 15:55:20]

jfb@chromium.org changed reviewers:
+ jfb@chromium.org

[JF, 2015-04-16 15:55:21]

lgtm

[jvoung (off chromium), 2015-04-16 16:07:43]

Committed patchset #1 (id:1) manually as
d88fa4fed707a60fd29ef9d382ca030818d115a1 (presubmit successful).