ARM64: Tests update

ARM64: Tests update

- Delete bad test (sql_stress4) which uses Thread.Abort which is not in
  .NET Core.
- Delete non-existing test (MarshalBoolArray)
- Update time-out for StringConcat4/StringConcat8 which usualy failed due to time-out.
- Made _opt_dbgexplicit5/_opt_relexplicit5 UNSTABLE which pass mostly when
  running twice in the lab.
- Delete bad test (b519927) which uses AppDomain.DefineDynamicAssembly
  which is not in .NET Core.
- Delete bad test (b16241) that has overflow conversion (from double to int).