If the result of a build is not directly executable on the host
system or needs an execution runtime for any other reason (e.g.,
cross-compiled ARM binaries on Intel, emscripten-generated JS
files, binaries built with Valgrind support) then the current test
runners cannot work with them. This patch makes test runners
execute binaries via a runtime given in the `$RUNTIME` environment
variable (if it is specified).
JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu