[ELF][MIPS] Do not use 'sed' to modify binary files

On Windows different versions of 'sed' work in different text/binary
mode by default. If default mode is text, sed produces corrupted binary
files. Unfortunately there is no standard command line option to select
the mode. Some 'sed' support '-b' to switch to binary mode, while other
ones support '--text' option and does not have '-b' option at all.

llvm-svn: 257471