Enforce --jit-debug test by another way

.travis.yml

@@ -59,10 +59,6 @@ env:
   - &make-test-only
     script:
       - $SETARCH make -s test TESTOPTS="${TESTOPTS=$JOBS -q --tty=no}"
-      - |- # allow extra test-all if specified
-        if [ -n $TEST_ALL_TESTS ]; then
-          $SETARCH make -s test-all -o exts TESTOPTS="${TESTOPTS} ${TEST_ALL_OPTS}" TESTS="$TEST_ALL_TESTS" RUBYOPT="-w"
-        fi
 
   - &gcc-8
     compiler: gcc-8
@@ -146,8 +142,6 @@ env:
     <<: *make-test-only
     env:
       - GEMS_FOR_TEST=
-      - TEST_MJIT_SYMBOLS=1
-      - TEST_ALL_TESTS=../test/ruby/test_jit.rb
       - cppflags='-DRUBY_DEBUG -DVM_CHECK_MODE=1 -DTRANSIENT_HEAP_CHECK_MODE -DRGENGC_CHECK_MODE -DENC_DEBUG'
 
   - &VM_CHECK_MODE

test/lib/jit_support.rb

@@ -30,7 +30,7 @@ module JITSupport
     ]
     args << '--jit-wait' if wait
     args << '--jit-save-temps' if save_temps
-    args << '--jit-debug' if ENV['TEST_MJIT_SYMBOLS'] == '1'
+    args << '--jit-debug' if defined?(@jit_debug) && @jit_debug
     args << '-e' << script
     base_env = { 'MJIT_SEARCH_BUILD_DIR' => 'true' } # workaround to skip requiring `make install` for `make test-all`
     if preloadenv = RbConfig::CONFIG['PRELOADENV'] and !preloadenv.empty?

test/ruby/test_jit_debug.rb

@@ -0,0 +1,8 @@
+require_relative 'test_jit'
+
+class TestJITDebug < TestJIT
+  def setup
+    # let `#eval_with_jit` use --jit-debug
+    @jit_debug = true
+  end
+end