DrawEngine: Don't drop large batches of points, lines and rectangles

Software transform expands each point, line and rectangle to four
vertices, and gave up on the whole draw when that didn't fit
VERTEX_BUFFER_MAX. Batching only counted input vertices, so a batch over
16384 points (or 32768 line or rectangle vertices) vanished silently,
whether it came from one PRIM or several merged ones. Count the expanded
vertices when batching, and submit a PRIM too big on its own in parts.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

GPU/Vulkan/DrawEngineVulkan.cpp

@@ -554,6 +554,7 @@ void DrawEngineVulkan::ResetAfterSkippedDraw() {
 	numDrawVerts_ = 0;
 	numDrawInds_ = 0;
 	vertexCountInDrawCalls_ = 0;
+	expandedVertsInDrawCalls_ = 0;
 	numVertsToDecode_ = 0;
 	decodeIndsCounter_ = 0;
 	decodeVertsCounter_ = 0;