meson: Enable testing in CI

[tesuji]

This PR:

• tests: Fix shellcheck warnings in playTests.sh
• tests: Do not use ../programs which is relative to tests dirs
• tests: Replace relative paths for zstd/tests dir
• Set shell options explicitly, not in shebang
• playTests: Replace echo -e with printf
• meson: Fix test-zstd
• meson: Fix legacy test
• meson: Enable testing in CI

One advantage of running meson test on CI is that tests are run
parallel by default. So test time is faster than running test with make.

Closes #1605

[terrelln]

The changes to playTests.sh look okay, but we'll have to see if it is working on BSD and Windows.

[tesuji]

Spurious fail in ARM Fuzz test? Could you restart it, @terrelln ?

[tesuji]

Never mind. I force-pushed new changes.

[terrelln]

The failing poolTest is not a problem with meson. It was broken by #1581. I'll let you know when it is fixed.

[tesuji]

Hm, test-zstd time in Meson is long compare to other build jobs. Mostly
because it is built in debug mode.

Should I change it to release build?

 1/14 valgrindTest                            OK      520.37 s 
 2/14 test-zstd                               OK      1890.98 s 
 3/14 test-fullbench-1                        OK      19.78 s 
 4/14 test-fullbench-2                        OK      14.32 s 
 5/14 test-fuzzer                             OK      276.83 s 
 6/14 test-zbuff                              OK      102.55 s 
 7/14 test-zstream-1                          OK      111.95 s 
 8/14 test-zstream-2                          OK       0.02 s 
 9/14 test-zstream-3                          OK      99.40 s 
10/14 test-longmatch                          OK       8.86 s 
11/14 test-invalidDictionaries                OK       0.01 s 
12/14 test-symbols                            OK       0.04 s 
13/14 test-decodecorpus                       OK      32.71 s 
14/14 test-poolTests                          OK       0.47 s 

[tesuji]

Result when tests are built with -O2 -g. Note that all these tests
run in parallel.

 1/14 valgrindTest                            OK      151.35 s
 2/14 test-zstd                               OK      809.36 s
 3/14 test-fullbench-1                        OK      17.59 s
 4/14 test-fullbench-2                        OK      14.18 s
 5/14 test-fuzzer                             OK      222.50 s
 6/14 test-zbuff                              OK      109.88 s
 7/14 test-zstream-1                          OK      118.53 s
 8/14 test-zstream-2                          OK       0.01 s
 9/14 test-zstream-3                          OK      79.52 s
10/14 test-longmatch                          OK       2.43 s
11/14 test-invalidDictionaries                OK       0.00 s
12/14 test-symbols                            OK       0.00 s
13/14 test-decodecorpus                       OK      33.33 s
14/14 test-poolTests                          OK       0.58 s

[terrelln]

Awesome, thanks!

I'll fix the pool test in a separate PR, it has some deadlocks and flakiness problems.