Intent of single_host_failed, Test_Check_Context_Cancellation

All 4 exact tests in this concept. Every test is marked by where it enters the hierarchy.

go.temporal.io/ 4 tests
- server/ 4 tests
  - service/ 4 tests
    
    frontend/ 4 tests
    
    TestHealthCheckerSuite/ 4 tests
    
    Test_Check_Mixed_Host_States_Edge_Cases/ 1 test
    
    go.temporal.io/server/service/frontend/TestHealthCheckerSuite/Test_Check_Mixed_Host_States_Edge_Cases/edge_case:_combined_failures_and_declined_just_over_threshold Inherited edge_case:_combined_failures_and_declined_just_over_threshold
    
    Test_Check_Single_Host_Scenarios/ 1 test
    
    go.temporal.io/server/service/frontend/TestHealthCheckerSuite/Test_Check_Single_Host_Scenarios/single_host_failed Introduced here
    
    go.temporal.io/server/service/frontend/TestHealthCheckerSuite/Test_Check_Context_Cancellation Introduced here
    
    go.temporal.io/server/service/frontend/TestHealthCheckerSuite/Test_Check_ServiceDetail_Populated Inherited Test_Check_ServiceDetail_Populated