Show test output for failed tests, remove -v flag

[loosebazooka]

Looks like I did the wrong thing in #3548

Remove the -v flags and include detailed failed test output instead.

This only applies to macOS/linux builds, windows runs its tests without using the gotest.sh script: https://github.com/GoogleContainerTools/skaffold/blob/master/.travis.yml#L49 (which probably doesn't need the -v flag either, I think I misunderstood what the default was as I didn't realize this script did what it did)

The difference in output is:
OLD:

=== Failed Tests ===                                                                                                      
pkg/skaffold/build/jib/TestGetSyncMapFromSystem/direct_only
pkg/skaffold/build/jib/TestGetSyncMapFromSystem

NEW:

=== Failed Tests ===
/pkg/skaffold/build/jib/TestGetSyncMapFromSystem/direct_only
    --- FAIL: TestGetSyncMapFromSystem/direct_only (0.00s)
        sync_test.go:126: *jib.SyncMap differ (-got, +want):   &jib.SyncMap{                     
                "/tmp/skaffold684430519/dep1": {                                                                          
                        Dest:     []string{"/target/dep1"},                                                               
                        FileTime: s"2020-01-23 15:05:53.741546968 -0500 EST",       
            -           IsDirect: true,                                                                                   
            +           IsDirect: false,                                                                                  
                },                                                                                                        
              }    
/pkg/skaffold/build/jib/TestGetSyncMapFromSystem
    --- FAIL: TestGetSyncMapFromSystem (0.00s)

example failure in travis:

• MacOS: https://travis-ci.com/GoogleContainerTools/skaffold/jobs/279436130#L337
• Linux: https://travis-ci.com/GoogleContainerTools/skaffold/jobs/279436129#L324

[codecov]

Codecov Report

Merging #3569 into master will increase coverage by 0.17%.
The diff coverage is n/a.

Impacted Files	Coverage Δ
pkg/skaffold/debug/debug.go	45.16% <0%> (-1.51%)	⬇️
pkg/skaffold/debug/transform.go	89.37% <0%> (+0.13%)	⬆️
pkg/skaffold/util/tar.go	52.87% <0%> (+13.16%)	⬆️
pkg/skaffold/initializer/init.go	51.16% <0%> (+13.95%)	⬆️
pkg/skaffold/build/buildpacks/metadata.go	100% <0%> (+72.72%)	⬆️

[loosebazooka]

hold up one second, might be outputting duplicate test outputs... done