Attempt to fix WebViewTest#testFlingScroll.

WebViewTest#testFlingScroll started failing consistently on some
devices. When testing manually on a device that passes the test, it was
observed that the fling only causes a scroll from position (0,0) to
(2,2) - the fling velocity is extremely low and the resulting scroll is
very tiny. It seems plausible that on some device resolution/screen
density combinations that this tiny fling might fail to scroll far
enough to register as different, especially since the position is
rounded to int. It's unclear what units the fling velocity is measured
in.

Since the test doesn't care about the actual values and is just trying to
verify that flinging causes *some* scrolling to happen, increase the
fling velocity by a factor of 100.

Bug: 142675258
Test: atest android.webkit.cts.WebViewTest#testFlingScroll
Change-Id: I9787778f372c0a28efef513e50fdfc3678848788
(cherry picked from commit e4b7207096e4dd477290e163800f077b8921c53e)