Partially allow failures in test-bundled-gems

Tests of minitest randomly fails with strange errors:
https://dev.azure.com/rubylang/ruby/_build/results?buildId=303
https://dev.azure.com/rubylang/ruby/_build/results?buildId=314

Instead of marking `continueOnError` for all, let me select
failure-allowed gems individually.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67428 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

Makefile.in

@@ -529,10 +529,17 @@ enc/encinit.$(OBJEXT): enc/encinit.c $(SETUP)
 
 cont.$(OBJEXT): $(COROUTINE_H)
 
+# Override this to allow failure of specific gems on CI
+TEST_BUNDLED_GEMS_ALLOW_FAILURES =
+
 test-bundled-gems-run:
 	$(Q) set -e; while read gem _; do \
-	  echo testing $$gem gem && \
-	  $(XRUBY) -C $(srcdir)/gems/src/$$gem -Ilib ../../../.bundle/bin/rake; \
+	  echo testing $$gem gem; \
+	  if echo $(TEST_BUNDLED_GEMS_ALLOW_FAILURES) | grep -q $$gem; then \
+	    $(XRUBY) -C $(srcdir)/gems/src/$$gem -Ilib ../../../.bundle/bin/rake || true; \
+	  else \
+	    $(XRUBY) -C $(srcdir)/gems/src/$$gem -Ilib ../../../.bundle/bin/rake; \
+	  fi; \
 	done < $(srcdir)/gems/bundled_gems
 
 update-src::

azure-pipelines.yml

@@ -7,6 +7,8 @@ jobs:
     matrix:
       bundled_gems:
         task: test-bundled-gems
+        TEST_BUNDLED_GEMS_ALLOW_FAILURES: |
+          minitest
       bundler:
         task: test-bundler
   steps:
@@ -24,7 +26,7 @@ jobs:
   - script: |
       TRAVIS=1 make $(task)
     displayName: "test"
-    continueOnError: true # test-bundled-gems and test-bundler are failing on Linux. TODO: fix them and remove this line.
+    continueOnError: true # test-bundler is failing on Linux. TODO: fix it and remove this line.
 
 - job: macOS
   pool:
@@ -37,6 +39,8 @@ jobs:
 #        task: test-spec
       bundled_gems:
         task: test-bundled-gems
+        TEST_BUNDLED_GEMS_ALLOW_FAILURES: |
+          minitest
       bundler:
         task: test-bundler
   steps: