Renderer: Fix deadlock when calling Renderer::draw() with a count of 0.

Tests: dEQP-VK.draw.basic_draw.draw_indirect.*
Tests: dEQP-VK.draw.basic_draw.draw_indexed_indirect.*
Bug: b/133127573
Change-Id: Ie64ae58d352d0fab23a0ce8811ce95c024e59367
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/31687
Tested-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
diff --git a/src/Device/Renderer.cpp b/src/Device/Renderer.cpp
index f039d0d..15f13fb 100644
--- a/src/Device/Renderer.cpp
+++ b/src/Device/Renderer.cpp
@@ -301,6 +301,8 @@
 
 	void Renderer::draw(const sw::Context* context, VkIndexType indexType, unsigned int count, int baseVertex, vk::Fence* fence, bool update)
 	{
+		if(count == 0) { return; }
+
 		#ifndef NDEBUG
 			if(count < minPrimitives || count > maxPrimitives)
 			{