client output goes to application output file

Try running this Python program:

import os
os.system('/bin/sh -c "echo hello" >temp.out')

with -c libopcodes.so. Overall this results in 3 outputs from dropcodes... but one of them goes in temp.out:

$ cat temp.out
hello
Top 15 opcode execution counts in 64-bit AMD64 mode:
          3079 : jnbe
      ...

This is cut down from a much larger build script which was failing when run with the opcodes client - one build step was writing a file read by another step, and the file was being polluted by opcodes output. Reproduced on x86_64 and AArch64.