Add test case: Link 2 ESSL fragment shader units

Test/baseResults/es-link1.frag.out

+es-link1.frag
+Shader version: 100
+0:? Sequence
+0:5  Function Definition: main( (global void)
+0:5    Function Parameters: 
+0:7    Sequence
+0:7      move second child to first child (temp mediump 4-component vector of float)
+0:7        'gl_FragColor' (fragColor mediump 4-component vector of float FragColor)
+0:7        Function Call: calculateColor( (global mediump 4-component vector of float)
+0:?   Linker Objects
+
+es-link2.frag
+Shader version: 100
+0:? Sequence
+0:5  Function Definition: calculateColor( (global mediump 4-component vector of float)
+0:5    Function Parameters: 
+0:7    Sequence
+0:7      Branch: Return with expression
+0:7        vector-scale (temp mediump 4-component vector of float)
+0:7          'varyingColor' (smooth in mediump 4-component vector of float)
+0:7          Constant:
+0:7            0.500000
+0:?   Linker Objects
+0:?     'varyingColor' (smooth in mediump 4-component vector of float)
+
+
+Linked fragment stage:
+
+
+Shader version: 100
+0:? Sequence
+0:5  Function Definition: main( (global void)
+0:5    Function Parameters: 
+0:7    Sequence
+0:7      move second child to first child (temp mediump 4-component vector of float)
+0:7        'gl_FragColor' (fragColor mediump 4-component vector of float FragColor)
+0:7        Function Call: calculateColor( (global mediump 4-component vector of float)
+0:5  Function Definition: calculateColor( (global mediump 4-component vector of float)
+0:5    Function Parameters: 
+0:7    Sequence
+0:7      Branch: Return with expression
+0:7        vector-scale (temp mediump 4-component vector of float)
+0:7          'varyingColor' (smooth in mediump 4-component vector of float)
+0:7          Constant:
+0:7            0.500000
+0:?   Linker Objects
+0:?     'varyingColor' (smooth in mediump 4-component vector of float)
+

Test/es-link1.frag

+#version 100
+
+mediump vec4 calculateColor();
+
+void main()
+{
+    gl_FragColor = calculateColor();
+}

Test/es-link2.frag

+#version 100
+
+varying mediump vec4 varyingColor;
+
+mediump vec4 calculateColor()
+{
+    return varyingColor * 0.5;
+}

Test/runtests

@@ -96,6 +96,7 @@ function runBulkTest {
 runBulkTest mains1.frag mains2.frag noMain1.geom noMain2.geom
 runBulkTest noMain.vert mains.frag
 runBulkTest link1.frag link2.frag link3.frag
+runBulkTest es-link1.frag es-link2.frag
 runBulkTest recurse1.vert recurse1.frag recurse2.frag
 runBulkTest 300link.frag
 runBulkTest 300link2.frag