Disable embedded bitmap test on iOS.

The TypefaceRenderingGM crashes on iOS when drawing an embedded
bitmap when requesting aliased rendering. The crash looks like

libTrueTypeScaler.dylib`<redacted> + 80
stop reason = EXC_BAD_ACCESS (code=EXC_ARM_DA_ALIGN, address=...)
->  0x330b19d0 <+80>: strd   r2, r3, [r5, #36]
    0x330b19d4 <+84>: movs   r3, #0x0
    0x330b19d6 <+86>: add    r2, sp, #0x28
    0x330b19d8 <+88>: ldr    r0, [r4, #0x4]

Disable testing embedded bitmaps on iOS for now.

BUG=skia:5530

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2140383004

Review-Url: https://codereview.chromium.org/2140383004
1 file changed