scripts: go_srcs_in_module to list go source + test files

The shell function go_srcs_in_module will list go test files
along with go src files in the specified module. This helps
in identifying the copyright header misses in test files.

Fixes etcd-io#14827

Signed-off-by: Bhargav Ravuri <bhargav.ravuri@infracloud.io>

scripts/test_lib.sh

@@ -108,7 +108,7 @@ function relativePath {
 # go_srcs_in_module [package]
 # returns list of all not-generated go sources in the current (dir) module.
 function go_srcs_in_module {
-  go list -f "{{with \$c:=.}}{{range \$f:=\$c.GoFiles  }}{{\$c.Dir}}/{{\$f}}{{\"\n\"}}{{end}}{{end}}" ./... | grep -vE "(\\.pb\\.go|\\.pb\\.gw.go)"
+  go list -f "{{with \$c:=.}}{{range \$f:=\$c.GoFiles  }}{{\$c.Dir}}/{{\$f}}{{\"\n\"}}{{end}}{{range \$f:=\$c.TestGoFiles  }}{{\$c.Dir}}/{{\$f}}{{\"\n\"}}{{end}}{{end}}" ./... | grep -vE "(\\.pb\\.go|\\.pb\\.gw.go)"
 }
 
 # pkgs_in_module [optional:package_pattern]