Previously we only copied the GLSL shader compiler's info log on
failure. This hid any warnings or debug info from the application.

Bug chromium:845103

Change-Id: Ia1877a405db2017d327dfc68037596fbda1579fa
Reviewed-on: https://swiftshader-review.googlesource.com/19009Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>