replace SkIRect[1] with SkIRect
replace SkIRect[1] with SkIRect

GCC 8 is still tripping on GrWindowRectangles for mips64el:

    ../SRC/skia/tests/WindowRectanglesTest.cpp:55:42:
    error: 'int __builtin_memcmp_eq(const void*, const void*, long unsigned int)'
    reading 112 bytes from a region of size 16 [-Werror=stringop-overflow=]
       REPORTER_ASSERT(reporter, !memcmp(B.data(), windowData,
                                         (GrWindowRectangles::kMaxWindows - 1) * sizeof(SkIRect)));

    ../SRC/skia/tests/WindowRectanglesTest.cpp:69:42:
    error: 'int __builtin_memcmp_eq(const void*, const void*, long unsigned int)'
    reading 128 bytes from a region of size 16 [-Werror=stringop-overflow=]
       REPORTER_ASSERT(reporter, !memcmp(B.data(), A.data(),
                                         GrWindowRectangles::kMaxWindows * sizeof(SkIRect)));

Both A and B are filled up to the kMaxWindows limit (8) at this point,
but GCC still clearly thinks .data() is returning the 16-byte
fLocalWindows SkIRect[1] array.

I was curious to see if removing the (currently pointless) array helps GCC
get the gist.  It doesn't, but I still kind of want to remove it.

Change-Id: I4ee9478b8c69061cb351d203d55749f68dcb939e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/257873
Commit-Queue: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>
Reviewed-by: Brian Osman <794c0b5534edf5601d88e1d41975d0262da12894@google.com>

google/skia,google/skia,HalCanary/skia-hc,google/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,google/skia,HalCanary/skia-hc,google/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,HalCanary/skia-hc,google/skia,google/skia,google/skia,HalCanary/skia-hc