tools: Rewrite test script
tools: Rewrite test script

Use the portable 'subprocess' module instead of the 'os' module
for subprocess management. Also, use the standard indentation of
4 spaces.

Signed-off-by: Jussi Virtanen <2a7e40f91a3be32dfb7e35af6e476a252ebdb4f3@gmail.com>

jvirtanen/libtrading,mstanichenko/libtrading,femtotrader/libtrading,svdev/libtrading,jvirtanen/libtrading,mstanichenko/libtrading,etoestja/libtrading,fengzhyuan/libtrading,penberg/libtrading,divaykin/libtrading,Bitcoinsulting/libtrading,penberg/libtrading,libtrading/libtrading,libtrading/libtrading,divaykin/libtrading,NunoEdgarGub1/libtrading,NunoEdgarGub1/libtrading,femtotrader/libtrading,etoestja/libtrading,fengzhyuan/libtrading,svdev/libtrading,Bitcoinsulting/libtrading