This patch adds GetTexLevelParameterivANGLE and GetTexLevelParameterfvANGLE.

TEST=TextureMultisampleTest.GetTexLevelParameter*
TEST=NegativeTextureMultisampleTest.Negtive*

BUG=angleproject:2275

Change-Id: Id702ba31df36ab65f46b697d480b5bf01b87e360
Reviewed-on: https://chromium-review.googlesource.com/c/1295830Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Yizhou Jiang <yizhou.jiang@intel.com>