Move the last gn_arg over to the rest

is_debug was the only configuration argument still set in gn_run.pro

Change-Id: I7b66888e6b936b44bafdad02f7974941d4e875ce
Reviewed-by: Michal Klocek <michal.klocek@qt.io>

src/core/config/common.pri

@@ -55,6 +55,7 @@ precompile_header {
 }
 
 CONFIG(release, debug|release) {
+    gn_args += is_debug=false
     force_debug_info {
         # Level 1 is not enough to generate all Chromium debug symbols on Windows
         msvc: gn_args += symbol_level=2
@@ -65,6 +66,7 @@ CONFIG(release, debug|release) {
 }
 
 CONFIG(debug, debug|release) {
+    gn_args += is_debug=true
     gn_args += use_debug_fission=false
 }
 

src/core/gn_run.pro

@@ -29,10 +29,6 @@ build_pass|!debug_and_release {
 
     gn_args = $$gnArgs()
 
-    CONFIG(release, debug|release) {
-        gn_args += is_debug=false
-    }
-
     gn_args += "qtwebengine_target=\"$$system_path($$OUT_PWD/$$getConfigDir()):QtWebEngineCore\""
 
     !qtConfig(webengine-system-gn) {