Fix infinite recursion in test browser.test_webgl_context_major_version.

[juj]

Fix infinite recursion in test browser.test_webgl_context_major_version.

abort() calls to err(), and the test would overwrite err() to call to abort().

The test would pass, but only after throwing

[890/960] test_webgl_context_major_version (test_browser.browser64_4gb.test_webgl_context_major_version) ... JavaScript error: http://localhost:8888/test.js, line 193: InternalError: too much recursion
JavaScript error: http://localhost:8888/test.js, line 193: InternalError: too much recursion
JavaScript error: http://localhost:8888/test.js, line 193: InternalError: too much recursion
JavaScript error: http://localhost:8888/test.js, line 193: InternalError: too much recursion
ok

http://clbri.com:8010/api/v2/logs/420471/raw_inline

[sbc100]

Oh wow, that is bad.

This test should probably just a different mechanism here, but LGTM to the fix.