Remove a major source of flaky service test failures.

runtime/observatory/tests/service/service.status

Index: runtime/observatory/tests/service/service.status
diff --git a/runtime/observatory/tests/service/service.status b/runtime/observatory/tests/service/service.status
index cee1a67b934fad15d35aa0f329b00d172a264a58..ae4f1096727d756a2ae6f25109643b4d536a041d 100644
--- a/runtime/observatory/tests/service/service.status
+++ b/runtime/observatory/tests/service/service.status
@@ -3,16 +3,9 @@
 # BSD-style license that can be found in the LICENSE file.
 
 # Flaky failures
-vm_timeline_flags_test: Pass, RuntimeError # Issue 26483
 gc_test: Pass, RuntimeError # Issue 26490
-pause_on_start_and_exit_test: Pass, RuntimeError # Issue 26470
-pause_on_start_then_step_test: Pass, RuntimeError # Issue 26470
 get_allocation_samples_test: Pass, RuntimeError # Inconsistent stack trace
-get_isolate_rpc_test: Pass, RuntimeError # Issue 28185
-set_library_debuggable_test: Pass, RuntimeError # Issue 28091
 reload_sources_test: Pass, Slow # Reload is slow on the bots
-rewind_test: Pass, RuntimeError # Issue 28047
-tcp_socket_service_test: Pass, RuntimeError # Issue 28184
 get_retained_size_rpc_test: Pass, RuntimeError # Issue 28193
 
 [ ($compiler == none || $compiler == precompiler) && ($runtime == vm || $runtime == dart_precompiled) ]