meson: Enable testing in CI (#1609)

* tests: Fix shellcheck warnings in playTests.sh

* tests: Do not use ../programs which is relative to tests dirs

This commit fixes error when running playTests.sh in Meson.
Mesonbuild runs out of tree, so ./datagen not in `zstd/tests` dir,
it lies in <mesonbuilddir>/tests. This leads to ../programs invalid.

* tests: Replace relative paths for zstd/tests dir

* playTests: Set shell options explicitly, not in shebang

* playTests: Replace echo -e with printf

* meson: Fix test-zstd

Use std=gnu99 to build and test just like `make test`.

* meson: Fix legacy test

* meson: Enable testing in CI

Run build under release mode for faster test time.

* meson: Increase timeout time for test-zstream

.travis.yml

@@ -190,14 +190,19 @@ matrix:
             && python3 ~/get-pip.py --user
             && pip3 install --user meson
       script:
-        - meson setup --buildtype=debug
-                -Db_lundef=false
-                -Dauto_features=enabled
-                -Dbuild_{programs,tests,contrib}=true
-                -Ddefault_library=both
-                build/meson builddir
+        - meson setup
+            --buildtype=debugoptimized
+            -Db_lundef=false
+            -Dauto_features=enabled
+            -Dbuild_{programs,tests,contrib}=true
+            -Ddefault_library=both
+             build/meson builddir
         - pushd builddir
+        - ninja
+        - meson test --verbose --no-rebuild
         - DESTDIR=./staging ninja install
         - tree ./staging
+      after_failure:
+        - cat "$TRAVIS_BUILD_DIR"/builddir/meson-logs/testlog.txt
   allow_failures:
     - env: ALLOW_FAILURES=true