[libcxx] Remove pragmas that were needed to suppress warnings produced
by -Wpadded.

We don't need these pragmas anymore because -Wpadded was removed from
buildit in r258900.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@259023 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed