[master] 32ea9c59d vtc: Flip the feature check in v4

[Dridi Boukelmoune]

commit 32ea9c59df6beeab94bb38c0b559a58686cb7f89
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Fri Jan 8 16:58:44 2021 +0100

    vtc: Flip the feature check in v4
    
    In order to run the test we want to NOT be using gcov, so we should test
    that the environment variable is empty. In theory that should mean that
    GCOV runs should currently fail since the feature check is currently
    backwards so I may revert this change if that suddenly happens.
    
    I find `test -z ...` more readable than `[ -z ... ]` in this context, so
    if it comes to a revert, I will keep the test(1) syntax.

diff --git a/bin/varnishtest/tests/v00004.vtc b/bin/varnishtest/tests/v00004.vtc
index f3a28062a..1cac50de0 100644
--- a/bin/varnishtest/tests/v00004.vtc
+++ b/bin/varnishtest/tests/v00004.vtc
@@ -3,7 +3,7 @@ varnishtest "test if our default paramers make sense ..."
 feature 64bit
 
 # Skip this test in GCOV mode, 68xx bytes extra per level makes it fail
-feature cmd {[ -n "$GCOV_PROG" ]}
+feature cmd {test -z "$GCOV_PROG"}
 
 # ... for our definition of a standard use case:
 # - 2019 header madness