fix check for non-positive array size

Test/baseResults/negativeArraySize.comp.out

@@ -0,0 +1,24 @@
+negativeArraySize.comp
+Warning, version 310 is not yet complete; most version-specific features are present, but some are missing.
+ERROR: 0:9: '' : array size must be a positive integer 
+ERROR: 1 compilation errors.  No code generated.
+
+
+Shader version: 310
+local_size = (1, 1, 1)
+ERROR: node is still EOpNull!
+0:7  Function Definition: main( (global void)
+0:7    Function Parameters: 
+0:?   Linker Objects
+
+
+Linked compute stage:
+
+
+Shader version: 310
+local_size = (1, 1, 1)
+ERROR: node is still EOpNull!
+0:7  Function Definition: main( (global void)
+0:7    Function Parameters: 
+0:?   Linker Objects
+

Test/negativeArraySize.comp

@@ -0,0 +1,10 @@
+#version 310 es
+
+#ifdef GL_ES
+precision mediump float;
+#endif
+
+void main()
+{
+   float f[-2]; // cannot declare arrays with negative size
+}

Test/testlist

@@ -128,4 +128,5 @@ varyingArrayIndirect.frag
 voidFunction.frag
 whileLoop.frag
 nonVulkan.frag
+negativeArraySize.comp
 spv.atomic.comp