Angular 6 Unit Test Coverage - reporting not accurate #26020

[x] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[ ] Performance issue
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question
[ ] Other... Please describe:

For Tooling issues:
- Node version: 8.11.3
- Platform:  Mac

Others:
      _                      _                 ____ _     ___
    / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
   / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
  / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
 /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                |___/


Angular CLI: 6.2.2
Node: 8.11.3
OS: darwin x64
Angular: 6.1.7
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.7.5
@angular-devkit/build-angular     0.7.5
@angular-devkit/build-optimizer   0.7.5
@angular-devkit/build-webpack     0.7.5
@angular-devkit/core              0.8.2
@angular-devkit/schematics        0.8.2
@angular/cli                      6.2.2
@ngtools/webpack                  6.1.5
@schematics/angular               0.8.2
@schematics/update                0.8.2
rxjs                              6.3.2
typescript                        2.7.2
webpack                           4.9.2