UNIFORM_BUFFER_OFFSET_ALIGNMENT set to 4

We previously had UNIFORM_BUFFER_OFFSET_ALIGNMENT set to 1. That
value was arbitrary, and WebGL expects that value to be 4, so I
made the change.

Fixes WebGL 2 test:
deqp/functional/gles3/negativebufferapi.html

Change-Id: I7ab654cce629ac2a5dffc9a9d3bff3c1fb1ec8c7
Reviewed-on: https://swiftshader-review.googlesource.com/16608
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/OpenGL/libGLESv2/Context.h b/src/OpenGL/libGLESv2/Context.h
index e7484ff..e2b517d 100644
--- a/src/OpenGL/libGLESv2/Context.h
+++ b/src/OpenGL/libGLESv2/Context.h
@@ -102,7 +102,7 @@
 	MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS = MAX_VERTEX_UNIFORM_BLOCKS_COMPONENTS + MAX_VERTEX_UNIFORM_COMPONENTS,
 	MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS = 4,
 	MAX_UNIFORM_BUFFER_BINDINGS = sw::MAX_UNIFORM_BUFFER_BINDINGS,
-	UNIFORM_BUFFER_OFFSET_ALIGNMENT = 1,
+	UNIFORM_BUFFER_OFFSET_ALIGNMENT = 4,
 	NUM_PROGRAM_BINARY_FORMATS = 0,
 };