Revert "Replace gl::trace logging with Chromium style logging"

Failing Chromium static initializers check:

FAILED linux-release-64/sizes/chrome-si/initializers: actual 8, expected 7, better lower

Possibly due to the static initializer for std::array for
the log severity types. We should change it to POD.

BUG=angleproject:1660

This reverts commit afcc41cee4ff63e7f6c9e60e55fc061adbba7dd4.

Change-Id: Ifb362a4af78542608397c7a0b19e6afe076f2cf3
Reviewed-on: https://chromium-review.googlesource.com/427235
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/validationES.cpp b/src/libANGLE/validationES.cpp
index 7547da3..f07b216 100644
--- a/src/libANGLE/validationES.cpp
+++ b/src/libANGLE/validationES.cpp
@@ -3159,8 +3159,8 @@
         {
             if (!context->getExtensions().webglCompatibility)
             {
-                ERR() << "This ANGLE implementation does not support separate front/back stencil "
-                         "writemasks, reference values, or stencil mask values.";
+                ERR("This ANGLE implementation does not support separate front/back stencil "
+                    "writemasks, reference values, or stencil mask values.");
             }
             context->handleError(Error(GL_INVALID_OPERATION));
             return false;
@@ -4611,7 +4611,7 @@
 
         // We also output an error message to the debugger window if tracing is active, so that
         // developers can see the error message.
-        ERR() << errorMessage;
+        ERR("%s", errorMessage);
         return false;
     }