tests: re-enable 1510, unignore 2027 2051 in GHA/macos, document heimdal memleak

- test1510: it was marked flaky, then disabled. Keep the flaky flag
  and allow it to run again.
  Ref: ef02da3156
  Ref: 0110cced2a

- GHA/linux: extend information about the heimdal valgrind failures.

- GHA/macos: unignore 2037 2041 in torture tests. They no longer
  appear flaky.
  Follow-up to 4b791dca37 #14667

Closes #17462

.github/workflows/linux.yml

@@ -680,7 +680,7 @@ jobs:
               TFLAGS+=' -j6'
             fi
             if [[ '${{ matrix.build.install_packages }}' = *'heimdal-dev'* ]]; then
-              TFLAGS+=' ~2077 ~2078'  # valgrind errors
+              TFLAGS+=' ~2077 ~2078'  # valgrind reporting memory leaks from Curl_auth_decode_spnego_message() -> gss_import_name()
             fi
           fi
           [ -x "$HOME/venv/bin/activate" ] && source $HOME/venv/bin/activate

.github/workflows/macos.yml

@@ -319,9 +319,6 @@ jobs:
         # zizmor: ignore[template-injection]
         run: |
           export TFLAGS='-j20 ${{ matrix.build.tflags }}'
-          if [ -z '${{ matrix.build.torture }}' ]; then
-            TFLAGS+=' ~2037 ~2041'  # flaky
-          fi
           source $HOME/venv/bin/activate
           rm -f $HOME/.curlrc
           if [ -n '${{ matrix.build.generate }}' ]; then

tests/data/DISABLED

@@ -46,9 +46,6 @@
 # fnmatch differences are just too common to make testing them sensible
 1307
 1316
-# test 1510 causes problems on the CI on GitHub
-# example: https://travis-ci.org/curl/curl/builds/81633600
-1510
 1512
 # test 1801 causes problems in CI builds
 # https://github.com/curl/curl/issues/380