Add more info for --type in run_tests.py and add android into all type

[eggfly]

It's a small improvement for --type help, for who want to use run_tests.py.

• More detail help info in run_tests.py and related other scripts flutter#95674

Pre-launch Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• I read and followed the [Flutter Style Guide] and the [C++, Objective-C, Java style guides].
• I listed at least one issue that this PR fixes in the description above.
• I added new tests to check the change I am making or feature I am adding, or Hixie said the PR is test-exempt. See [testing the engine] for instructions on
  writing and running engine tests.
• I updated/added relevant documentation (doc comments with ///).
• I signed the [CLA].
• All existing and new tests are passing.

[chinmaygarde]

The doc changes lgtm. But this changes the default behavior of the script. Not sure if this is the cause of the CI failure. But I agree, this all should include android.

[eggfly]

The doc changes lgtm. But this changes the default behavior of the script. Not sure if this is the cause of the CI failure. But I agree, this all should include android.

Yes it changes the behavior, and I think it should include android into all, so I add it.

The CI failure is in shell_unittests, seems like it's not related to android tests(android test is an apk installed into a device). Let me try the CI checking again.

[eggfly]

@chinmaygarde The last failed CI log:

• https://cirrus-ci.com/task/4554506837950464

Maybe the shell_unittest is flaky or failed and then fixed.

Now the CI test passed!

grep -nr run_tests.py . found:

./shell/platform/android/test/README.md:22:5. Build and run with `testing/run_tests.py [--type=java] [--java-filter=<test_class_name>]`.
./ci/builders/windows_host_engine.json:33:                    "script": "flutter/testing/run_tests.py",
./testing/dart/observatory/README.md:4:The `run_tests.py` script disables the observatory for other tests in the
./testing/ios/IosUnitTests/README.md:11:flutter/testing/run_tests.py --type=objc
./testing/ios/IosUnitTests/README.md:18:into Xcode after running `run_tests.py`, only a few basic tests will appear
./testing/ios/IosUnitTests/README.md:25:[`run_tests.py`](../../run_tests.py) again.
./testing/run_tests.sh:8:python "${CURRENT_DIR}/run_tests.py" --variant="${BUILD_VARIANT}" --type=engine,dart,benchmarks
./testing/analyze_core_dump.sh:5:# This script can be invoked by the run_tests.py script after an
./lib/spirv/README.md:39:To test the exception tests directly: `./testing/run_tests.py --type dart --dart-filter spirv_exception_test.dart`
./lib/spirv/README.md:49:To test the pixel tests directly: `./testing/run_tests.py --type dart --dart-filter fragment_shader_test.dart`

grep -nr run_tests . | grep all and found nothing.

These scripts seems like they are rarely using the all type. So I think it's OK.

The last failed CI log:

[ RUN      ] ShellTest.DiscardLayerTreeOnResize
../../flutter/shell/common/shell_unittests.cc:2373: Failure
Expected equality of these values:
  1
  external_view_embedder->GetSubmittedFrameCount()
    Which is: 2
[FATAL:flutter/fml/memory/weak_ptr.h(253)] Check failed: (checker_.checker).IsCreationThreadCurrent(). 
[ERROR:flutter/fml/backtrace.cc(116)] Caught signal SIGABRT during program execution.
Frame 0: 0x7fc33867442a abort
Frame 1: 0x26bcec9 Unknown
Frame 2: 0x26bcea8 fml::LogMessage::~LogMessage()
Frame 3: 0x260ee4c fml::WeakPtrFactory<>::CheckThreadSafety()
Frame 4: 0x2602cc9 fml::WeakPtrFactory<>::~WeakPtrFactory()
Frame 5: 0x25ad594 flutter::Shell::~Shell()
Frame 6: 0x22db9ab std::__1::default_delete<>::operator()()
Frame 7: 0x22db92c std::__1::unique_ptr<>::reset()
Frame 8: 0x22d8889 std::__1::unique_ptr<>::~unique_ptr()
Frame 9: 0x24082cd flutter::testing::ShellTest_DiscardLayerTreeOnResize_Test::TestBody()
Frame 10: 0x42b97bb testing::internal::HandleSehExceptionsInMethodIfSupported<>()
Frame 11: 0x42a9d67 testing::internal::HandleExceptionsInMethodIfSupported<>()
Frame 12: 0x42993c3 testing::Test::Run()
Frame 13: 0x4299a84 testing::TestInfo::Run()
Frame 14: 0x429a08d testing::TestSuite::Run()
Frame 15: 0x42a3851 testing::internal::UnitTestImpl::RunAllTests()
Frame 16: 0x42bcbfb testing::internal::HandleSehExceptionsInMethodIfSupported<>()
Frame 17: 0x42ab7a7 testing::internal::HandleExceptionsInMethodIfSupported<>()
Frame 18: 0x42a344f testing::UnitTest::Run()
Frame 19: 0x40d6931 RUN_ALL_TESTS()
Frame 20: 0x40d67b2 main
Frame 21: 0x7fc3386602e1 __libc_start_main
Frame 22: 0x22c532a _start
<<<<<<<<<<<<<<<<<<<<<
Command run successfully in 8.25 seconds: /tmp/clean_engine/src/out/host_debug_unopt/exe.unstripped/fml_unittests --gtest_filter=-*TimeSensitiveTest* --gtest_repeat=2 --gtest_shuffle
Running runtime_unittests in /tmp/clean_engine/src

[zanderso]

lgtm