Loosen restriction on F16 surfaces - allow "legacy" F16 mode

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4231

Change-Id: I032cdf82468ca11639760eb99773a88a5808ebe6
Reviewed-on: https://skia-review.googlesource.com/4231
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
diff --git a/tests/SurfaceTest.cpp b/tests/SurfaceTest.cpp
index 483a115..908dc16 100644
--- a/tests/SurfaceTest.cpp
+++ b/tests/SurfaceTest.cpp
@@ -944,7 +944,7 @@
         { kN32_SkColorType,       srgbColorSpace,   true,  "N32-srgb"    },
         { kN32_SkColorType,       adobeColorSpace,  true,  "N32-adobe"   },
         { kN32_SkColorType,       oddColorSpace,    false, "N32-odd"     },
-        { kRGBA_F16_SkColorType,  nullptr,          false, "F16-nullptr" },
+        { kRGBA_F16_SkColorType,  nullptr,          true,  "F16-nullptr" },
         { kRGBA_F16_SkColorType,  linearColorSpace, true,  "F16-linear"  },
         { kRGBA_F16_SkColorType,  srgbColorSpace,   false, "F16-srgb"    },
         { kRGBA_F16_SkColorType,  adobeColorSpace,  false, "F16-adobe"   },