Merge SwiftShader changes down from master

This fixes FP16 and several other problems.

We still fail 4 CTS tests on cf_x86_phone:

  android.graphics.cts.ImageDecoderTest.testWarpedDng
  android.graphics.cts.ImageDecoderTest.testUpscale
  android.graphics.drawable.cts.GradientDrawableTest.testSetColorList
  android.graphics.drawable.cts.ShapeDrawableTest.testMutateGetShape

Change-Id: I92f08d4042cc9ea5d32a4fd610c3adb8d9531b99
Bug: 75229322
Bug: 75778024
Bug: 76437145
Bug: 78194651
Test: Local build and atest CtsGraphicsTestCases