[Tizen][GPU][Perf] Prevent GPU scheduler from thrashiing.

This PR turns off pre-empty scheduling. On highend machines, pre-empty
scheduling reduces the latency of GPU commands. However, on Tizen mobile, this
can cause the kernel to thrash between generating GPU commands and executing
them. Android already turned off pre-empty scheduling also.

In addition, this PR is related to the private HW issue. Refer to
https://crosswalk-project.org/jira/browse/XWALK-348?focusedCommentId=13435&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13435

BUG=https://crosswalk-project.org/jira/browse/XWALK-348
Merge pull request #106 from ds-hwang/gpubug

[Tizen][GPU][Perf] Prevent GPU scheduler from thrashiing.