ANGLE: Fix Windows Store D3D Trim and Level 9 requirements

Due to additional validation not covered in previous patches, the Windows
Store certification compatibility had regressed. These changes ensure that
the required D3D behaviors are met.

Change-Id: I0a74f0d2fecaa87d4a9409da3a7a194254609759
Task-number: QTBUG-38481
Reviewed-by: Samuel Nevala <samuel.nevala@intopalo.com>
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@theqtcompany.com>
Reviewed-by: Jani Heikkinen <jani.heikkinen@theqtcompany.com>