[infra] Temporary revert bad_build_check until most of the targets get fixed. (#831)

Need to take a closer look at the following issues:
- https://github.com/google/oss-fuzz/issues/815
- https://github.com/google/oss-fuzz/issues/816
- https://github.com/google/oss-fuzz/issues/817
- https://github.com/google/oss-fuzz/issues/818
- https://github.com/google/oss-fuzz/issues/819
- https://github.com/google/oss-fuzz/issues/820
- https://github.com/google/oss-fuzz/issues/821
- https://github.com/google/oss-fuzz/issues/822
- https://github.com/google/oss-fuzz/issues/823
- https://github.com/google/oss-fuzz/issues/824
- https://github.com/google/oss-fuzz/issues/825
- https://github.com/google/oss-fuzz/issues/826
- https://github.com/google/oss-fuzz/issues/827
- https://github.com/google/oss-fuzz/issues/828
- https://github.com/google/oss-fuzz/issues/829
- https://github.com/google/oss-fuzz/issues/830

infra/gcb/build.py

@@ -185,9 +185,6 @@ def get_build_steps(project_yaml, dockerfile_path):
 
       env.append('OUT=' + out)
 
-      # To disable running of all fuzz targets while doing |test_all| step.
-      env.append('SKIP_TEST_TARGET_RUN=1')
-
       workdir = workdir_from_dockerfile(dockerfile_path)
       if not workdir:
         workdir = '/src'
@@ -209,17 +206,6 @@ def get_build_steps(project_yaml, dockerfile_path):
               'rm -r /out && cd /src && cd {1} && mkdir -p {0} && compile && rm -rf /work && rm -rf /src'.format(out, workdir),
             ],
           },
-          # test binaries
-          {'name': 'gcr.io/oss-fuzz-base/base-runner',
-            'env': env,
-            'args': [
-              'bash',
-              '-c',
-              # Verify that fuzzers have been built properly and are not broken.
-              # TODO(mmoroz): raise a notification if not passing the tests.
-              'test_all'
-            ]
-          },
           # zip binaries
           {'name': image,
             'args': [