Reland "Remove GrCaps::SupportedRead::fSwizzle and supporting code"

This reverts commit a0f864d6acda0d526d3901d0d26e9393aee04115.

Reason for revert: updated valgrind suppression

EXTRA_TRYBOTS=Test-Ubuntu18-GCC-Golo-GPU-QuadroP400-x86_64-Release-All-Valgrind_SK_CPU_LIMIT_SSE41

Original change's description:
> Revert "Remove GrCaps::SupportedRead::fSwizzle and supporting code"
>
> This reverts commit 1cec69ae5cdc2c183f6a2115d60ebdf796a89a92.
>
> Reason for revert: Causing Valgrind failures
>
> Original change's description:
> > Remove GrCaps::SupportedRead::fSwizzle and supporting code
> >
> > Add weird color types that handle the swizzling.
> >
> > Change-Id: Ie37a00eb877fe5e519f7498bf749e02a2f1dc204
> > Reviewed-on: https://skia-review.googlesource.com/c/skia/+/230135
> > Reviewed-by: Greg Daniel <egdaniel@google.com>
> > Commit-Queue: Brian Salomon <bsalomon@google.com>
>
> TBR=egdaniel@google.com,bsalomon@google.com
>
> Change-Id: I710e1952f2cef1a1e6e7ccf408b8a71ce721c002
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/231262
> Reviewed-by: Ben Wagner aka dogben <benjaminwagner@google.com>
> Commit-Queue: Ben Wagner aka dogben <benjaminwagner@google.com>

TBR=egdaniel@google.com,bsalomon@google.com,benjaminwagner@google.com

Change-Id: I367f62ba7349b112d0a2eb5340a37be938ad5ef5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/231178
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/SkGr.cpp b/src/gpu/SkGr.cpp
index 09a93a2..668448b 100644
--- a/src/gpu/SkGr.cpp
+++ b/src/gpu/SkGr.cpp
@@ -308,6 +308,9 @@
         case GrColorType::kRGBA_F16:
         case GrColorType::kRGBA_F16_Clamped:
         case GrColorType::kAlpha_8:
+        case GrColorType::kAlpha_8xxx:
+        case GrColorType::kAlpha_F32xxx:
+        case GrColorType::kGray_8xxx:
             return -1;
     }
     SkUNREACHABLE;