Improve D3D11 varying packing when there are more varyings than registers.

BUG=angle:738

Change-Id: I0599840fc79d571230acf26105d512322bcffdcd
Reviewed-on: https://chromium-review.googlesource.com/214108
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libGLESv2/ProgramBinary.cpp b/src/libGLESv2/ProgramBinary.cpp
index 2e755df..1cc55d2 100644
--- a/src/libGLESv2/ProgramBinary.cpp
+++ b/src/libGLESv2/ProgramBinary.cpp
@@ -1072,6 +1072,7 @@
                 }
 
                 output->registerIndex = input->registerIndex;
+                output->columnIndex = input->columnIndex;
 
                 matched = true;
                 break;