Sync and assert StandardPixmap enums in QPlatformTheme and QStyle

Add missing enum values in QPlatformTheme::standardPixmap to sync with
QStyle::standardPixmap changes from:
785d2b9d0728bbbc0d2a92b7d4186a3114d54128
aa5a595a98f1af4a514485268a18e6cb9cfec783

Add enum values NStandardPixmap at the bottom of both enums as well
as an assertion in QStyle constructor that these values are identical.
Add omitvalue for NStandardPixmap in QStyle (QPlatformTheme enum is
not documented).

Change-Id: I9ee528d032c445bed5aeace716893b2af8367de2
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 2f4204238c7ec6f52b688268b6d3b4b937630074)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/gui/kernel/qplatformtheme.h

@@ -230,6 +230,16 @@ public:
         MediaVolume,
         MediaVolumeMuted,
         LineEditClearButton,
+        DialogYesToAllButton,
+        DialogNoToAllButton,
+        DialogSaveAllButton,
+        DialogAbortButton,
+        DialogRetryButton,
+        DialogIgnoreButton,
+        RestoreDefaultsButton,
+        TabCloseButton,
+        NStandardPixmap, // assertion value for sync with QStyle::StandardPixmap
+
         // do not add any values below/greater than this
         CustomBase = 0xf0000000
     };

src/widgets/styles/qstyle.cpp

@@ -376,6 +376,9 @@ QStyle::QStyle(QStylePrivate &dd)
 {
   Q_D(QStyle);
   d->proxyStyle = this;
+  Q_STATIC_ASSERT_X(int(StandardPixmap::NStandardPixmap) ==
+                    int(QPlatformTheme::StandardPixmap::NStandardPixmap),
+                    "StandardPixmap in QPlatformTheme and QStyle out of sync");
 }
 
 /*!
@@ -2084,6 +2087,7 @@ void QStyle::drawItemPixmap(QPainter *painter, const QRect &rect, int alignment,
     \value [since 5.14] SP_DialogIgnoreButton Icon for a standard Ignore button in a QDialogButtonBox.
     \value [since 5.14] SP_RestoreDefaultsButton Icon for a standard RestoreDefaults button in a QDialogButtonBox.
     \value [since 6.3] SP_TabCloseButton Icon for the close button in the tab of a QTabBar.
+    \omitvalue NStandardPixmap
     \value SP_CustomBase  Base value for custom standard pixmaps;
     custom values must be greater than this value.
 

src/widgets/styles/qstyle.h

@@ -791,6 +791,7 @@ public:
         SP_DialogIgnoreButton,
         SP_RestoreDefaultsButton,
         SP_TabCloseButton,
+        NStandardPixmap, // assertion value for sync with QPlatformTheme::StandardPixmap
         // do not add any values below/greater than this
         SP_CustomBase = 0xf0000000
     };