Update webgl-depth-texture.html in ToT and 1.0.2 suites.

We no longer ask for RGBA to match.  The updated extension spec only guarantees the R channel.
Fix a typo in webgl-depth-texture.html
Fixed min-version of newly added test.
Merge pull request #404 from kenrussell/test-version

Fixed min-version of newly added test.
Merge pull request #402 from zhenyao/depth

Update webgl-depth-texture.html in ToT and 1.0.2 suites.