Merge changes Ib3f4ee14,Iac22c9fd,Ibd78758c,I40d8696c,I2a2b10e4, ...

* changes:
  Fix InstallBypassMake symlink dependencies
  Add tests for ctx.InstallFile
  Fix OutDir vs SoongOutDir in tests
  Fix go vet error
  Add missing os.MkdirAll to WriteFileToOutputDir
  Use pathtools.WriteFileIfChanged in translateAndroidMk