Added the command to send the clear color image command
to the Image object.

Bug b/118619338

Change-Id: Ic4e00fbd49e8e043df1d2e707e3c26dadf159790
Reviewed-on: https://swiftshader-review.googlesource.com/c/23653Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Corentin Wallez <cwallez@google.com>