[asan] Re-enable test/asan/TestCases/Linux/recvfrom.cc testcase.
[asan] Re-enable test/asan/TestCases/Linux/recvfrom.cc testcase.

This testcase failed on sanitizer-x86_64-linux buildbot in large parallel build due to race on
port 1234 between AddressSanitizer-i386-linux and AddressSanitizer-x86_64-linux instances of recvfrom.cc.
This patch tries to resolve the issue by relying on kernel to choose available port instead of hardcoding
its number in testcase.

Differential Revision: http://reviews.llvm.org/D17639


git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@262204 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt