Fix ci.sh tests on arm qemu systems

There are two problems:
* The x86 JIT compiler requires detectFeatures, defined in the x86 assembly.
  Thus it can't (currently) be built on non-x86 platforms.
  For the purposes of fixing test/ci.sh, it suffices to pretend
  codegen-targets=all means codegen-targets=native when on arm.
* Qemu can introduce some extra latency which was regularly screwing up the LinkedBlockingQueueTest.
  Solution: increase the timeout to 1/10th seconds.
ci.sh: control which target is run for each of the configurations

There are two important things here:
* We only want to run "jdk-test" if we were running "test" for everything else.
  This gets around a bug where jdk-test fails for cross-compile builds (where JNI is involved)
* We can specify a different test target by setting the "test" environment variable.
  This is useful for cross-compiling the tests in a docker image
  (setting the test_target to "build-test")
Merge pull request #250 from joshuawarner32/fix-tests

Fix ci.sh tests on arm qemu systems