Remove redundant -mattr options from llvm-objdump commands.

Remove redundant -mattr options from llvm-objdump commands.

The -mattr options in these four tests have no effect on the output of
llvm-objdump. In the case of the two Mips tests, removing the -mattr option
left duplicate RUN lines so the duplicates have been removed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272906 91177308-0d34-0410-b5e6-96231b3b80d8