test: fix test runner execvp async-signal-safety
test: fix test runner execvp async-signal-safety

execvp() is not async-signal-safe, execve() is.

PR-URL: https://github.com/libuv/libuv/pull/2056
Reviewed-By: Gireesh Punathil <2a354d5071a77b10e33b207c224966bfe59b0626@in.ibm.com>
Reviewed-By: Santiago Gimeno <3f17e29e343c4cf8809fb0970d81d6d8ee88d6b3@gmail.com>

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso