vertexAttribPointer must restrict offset parameter

vertexAttribPointer must restrict offset parameter
https://bugs.webkit.org/show_bug.cgi?id=196261
<rdar://problem/48458086>

Reviewed by Antoine Quint.

Source/WebCore:

This WebGL function should fail if the offset parameter is
not within [0, max 32-bit int].

Test: fast/canvas/webgl/vertexAttribPointer-with-bad-offset.html

* html/canvas/WebGLRenderingContextBase.cpp:
(WebCore::WebGLRenderingContextBase::vertexAttribPointer):

LayoutTests:

Add a test where the offset parameter is out of bounds.

* fast/canvas/webgl/vertexAttribPointer-with-bad-offset-expected.txt: Added.
* fast/canvas/webgl/vertexAttribPointer-with-bad-offset.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@243506 268f45cc-cd09-0410-ab3c-d52691b4dbfc