Fix slow run time of OpPhi wide test

dEQP-VK.spirv_assembly.instruction.compute.opphi.wide was using 1024
arguments for OpPhi SpirV instruction. This was causing very slow
run/compile time on some devices and therefore failing the test due to
timeout.

This CL halves the number of arguments given to the OpPhi instruction to
avoid timeouts.

Affects:

dEQP-VK.spirv_assembly.instruction.compute.opphi.wide

VK-GL-CTS Issue: 2681

Components: Vulkan
Change-Id: Ice41e983b8da866916e07c1b52d7ccfd65001077
diff --git a/external/vulkancts/modules/vulkan/spirv_assembly/vktSpvAsmInstructionTests.cpp b/external/vulkancts/modules/vulkan/spirv_assembly/vktSpvAsmInstructionTests.cpp
index 11004e7..8c866fe 100644
--- a/external/vulkancts/modules/vulkan/spirv_assembly/vktSpvAsmInstructionTests.cpp
+++ b/external/vulkancts/modules/vulkan/spirv_assembly/vktSpvAsmInstructionTests.cpp
@@ -3659,7 +3659,7 @@
 	vector<float>					outputFloats4	(numElements, 0);
 	vector<float>					outputFloats5	(numElements, 0);
 	std::string						codestring		= "ABC";
-	const int						test4Width		= 1024;
+	const int						test4Width		= 512;
 
 	// Build case 5 code string. Each iteration makes the hierarchy more complicated.
 	// 9 iterations with (7, 24) parameters makes the hierarchy 8 deep with about 1500 lines of