Fix flag typo and add '--enable-gpu-rasterization' to ensure rendering test hits YUV

"--disable--oop-rasterization" --> "--disable-oop-rasterization"!

Follow-up for https://chromium-review.googlesource.com/c/chromium/src/+/1626504

This will give us decode improvement numbers on Mac and Windows for
webp_decoding_yuv_and_gpu_rasterization.

Bug: 900264
Change-Id: I63947a982274814e3bdd7c5635b3452c0b7ec162
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1636931
Auto-Submit: Madeleine Barowsky <mbarowsky@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Madeleine Barowsky <mbarowsky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#665727}

tools/perf/page_sets/rendering/rendering_stories.py

@@ -63,7 +63,8 @@ class RenderingStorySet(story.StorySet):
           story_tags.IMAGE_DECODING in story_class.TAGS and
           story_tags.GPU_RASTERIZATION in story_class.TAGS):
         required_args += ['--force-gpu-rasterization',
-                          '--disable--oop-rasterization']
+                          '--enable-gpu-rasterization',
+                          '--disable-oop-rasterization']
         # Run RGB decoding with GPU rasterization (to be most comparable to YUV)
         self.AddStory(story_class(
             page_set=self,