[M108 Migration][WebGL] Disable |CommandBufferHelper| auto flushing.
If |automatic_flushes| is true, buffer of |CommandBufferHelper| is flushed
automatically and it causes sync message calls. Due to this main thread is
blocked and performance degradation is observed.
+--------------------+--------+--------+
| KPI | Before | After |
+--------------------+--------+--------+
| 3D/Aquarium | 35~60 | ~60 |
+--------------------+--------+--------+
| 3D/100 Objects | 35~60 | ~60 |
+--------------------+--------+--------+
(Target : TV)
Reference: https://review.tizen.org/gerrit/265363
Change-Id: If287b3b4d12e29c159a70361d251b871377c6818
Signed-off-by: uzair <uzair.jaleel@samsung.com>