Revert "Transform verts using nonsquare matrices in FPs."

This reverts commit f3c38a3d0a43827c3849f06d13febb1e647b307e.

Reason for revert: this breaks the Chrome roll

Original change's description:
> Transform verts using nonsquare matrices in FPs.
>
> IF THE CHROME ROLL BREAKS, ROLL BACK THIS CL!
>
> This relands one portion of http://review.skia.org/403079, which was
> rolled back due to a Chrome roll issue (a pixel-gap introduced in a form
> rendering test).
>
> Change-Id: I3d8f900c80c79f20e876ae360a93febe16a0a4bc
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/406836
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Brian Salomon <bsalomon@google.com>
> Commit-Queue: John Stiles <johnstiles@google.com>
> Auto-Submit: John Stiles <johnstiles@google.com>

TBR=bsalomon@google.com,brianosman@google.com,johnstiles@google.com

Change-Id: I45fced067ee18acfc7a36273bf9421f55eeaab5e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/407096
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
diff --git a/src/gpu/glsl/GrGLSLFragmentProcessor.cpp b/src/gpu/glsl/GrGLSLFragmentProcessor.cpp
index 86f06ad..6bdda09 100644
--- a/src/gpu/glsl/GrGLSLFragmentProcessor.cpp
+++ b/src/gpu/glsl/GrGLSLFragmentProcessor.cpp
@@ -114,10 +114,6 @@
         if (childProc->sampleUsage().fHasPerspective) {
             return SkStringPrintf("%s(%s, proj((%s) * %s.xy1))", fFunctionNames[childIndex].c_str(),
                                   inputColor, matrixExpr.c_str(), args.fSampleCoord);
-        } else if (args.fShaderCaps->nonsquareMatrixSupport()) {
-            return SkStringPrintf("%s(%s, float3x2(%s) * %s.xy1)",
-                                  fFunctionNames[childIndex].c_str(), inputColor,
-                                  matrixExpr.c_str(), args.fSampleCoord);
         } else {
             return SkStringPrintf("%s(%s, ((%s) * %s.xy1).xy)", fFunctionNames[childIndex].c_str(),
                                   inputColor, matrixExpr.c_str(), args.fSampleCoord);