Allow drawing raster cache results whose device rect is one pixel larger than the cached image (#17278)

RasterCacheResult::draw constructs the device target rectangle by
calling SkRect::roundOut, which rounds down the left/top coordinates
and rounds up the right/bottom coordinates.  The rounding can produce
a device rect whose width and/or height differs from the cache result
image's width/height by one pixel.

On Fuchsia, we can now get executable VMOs from trusted backing
filesystems.  This allows us to remove the use of replace_as_executable
in favor of opening files with `fdio_open_fd_at` with the
`OPEN_RIGHT_EXECUTABLE` flag and getting VMOs by calling
`fdio_get_vmo_exec`.

By moving the responsibility for executability into the filesystem, we
are able to remove `deprecated-ambient-replace-as-executable` from
component manifests for non-JIT runners (the JIT runners still call
replace_as_executable in Dart's allocator).  It wasn't abundantly clear
whether .cmx files for tests were used purely in AOT runtime
environments or also saw JIT usage, so I left those as-is.

For context: this is a second attempt at #16690, which was reverted
because it broke the Dart JIT runner.  The primary difference is that
this time around, we correctly handle absolute vs relative paths,
depending on whether library loading bottoms out in `fdio_open_fd` or
`fdio_open_fd_at`.  I've added additional assertions to help ensure any
new usages use the correct shape of path.

Testing: I verified locally that the flutter product runner works on
Astro, and also successfully ran the Dart JIT example test (which was
the thing blocking the google3 roll with the previous attempt at this
patchset).
Co-authored-by: NDrew Fisher <zarvox@google.com>

* Switch ui.window.devicePixelRatio to browser dpi
* Add integration test for multi res image loading
* Update cirrus for new integration test
* update canvas golden test root transform
* Update compositing golden test with dpr transform

This folder is generated by the integration test manager.

This lets us measure stats on when the frame was
scheduled to be rendered vs when it finished rasterizing.

Note: This isn't propagated to the FrameTimings struct yet,
that is to be followed.

Rename GPU to raster thread in PerformanceOverlay and update goldens.

Fixes https://github.com/flutter/flutter/issues/53114

* use web drivers as a library only. do not fetch/clone web_installers

* fixing comments

* addressing reviewer comments

* adding a trim to output. otherwise last fails

* [fuchsia] Add labels to Scenic nodes.

* [fuchsia] Skip creating Scenic nodes for identity Transforms.

* [fuchsia] Assign elevation to Scenic nodes based on paint order.

* [fuchsia] Create Scenic OpacityNodes at leaf nodes.

* [fuchsia] Composite PhysicalShapeLayers using Skia, except when they need to float above child views.

In that case, they will still need to be pulled
into separate Scenic nodes to be composited on top
of the child view[s].

* [fuchsia] Add tests for Fuchsia-specific layer behavior.

Inspect commands going to Scenic and make sure
they match what is expected.

Also, restructure code to need less member variables,
and other cleanups based on review feedback.

Removed a text input trait that causes VoiceOver to be incorrect when tapping a text input. (#17203)