Disable UNIMPLEMENTED in ProgramGL::validateSamplers.

Removing this allows many angle end2end tests to run without hitting any
UNIMPLEMENTEDs.

BUG=angleproject:882

Change-Id: Idb55fae7b6fc7b23bc85d0bf376499f28669d771
Reviewed-on: https://chromium-review.googlesource.com/263250
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/renderer/gl/ProgramGL.cpp b/src/libANGLE/renderer/gl/ProgramGL.cpp
index 735ff4e..fd4c996 100644
--- a/src/libANGLE/renderer/gl/ProgramGL.cpp
+++ b/src/libANGLE/renderer/gl/ProgramGL.cpp
@@ -336,7 +336,7 @@
 
 bool ProgramGL::validateSamplers(gl::InfoLog *infoLog, const gl::Caps &caps)
 {
-    UNIMPLEMENTED();
+    //UNIMPLEMENTED();
     return true;
 }