Fix CONFIG += cmdline testcase creating app bundle paths in Makefiles

Fix an issue where qmake on macOS will generate a Makefile with a path
to a macOS bundle instead of a bundle-less executable in the Makefile's
check rule if cmdline is specified before testcase in the CONFIG
options.

Fixes: QTBUG-80280
Change-Id: Icc9ee1355b0641981ce79526b36f29957e1afb00
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

mkspecs/features/testcase.prf

@@ -9,6 +9,9 @@ testcase_exceptions: CONFIG += exceptions
 # Set in qt_build_config.prf
 testcase_no_bundle: CONFIG -= app_bundle
 
+# cmdline may have been specified and not processed yet
+cmdline: CONFIG -= app_bundle
+
 # Allow testcases to mark themselves as not supporting high-DPI
 testcase_lowdpi {
     macos {