skia: Fix aliasing violations

With the worst violations moved to skia/legacy, this has become
fixable -- fix the remaining aliasing violations and get rid of
-fno-strict-aliasing

Change-Id: I5b30058c01711f6eb4fb2f63a77f89ff183433b8
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>