There were four places where we did essentially the same steps in
order to extract the initial map for inlining a JSCreate operation.
This CL creates a function on NodeProperties for this task.

As a side effect, this fixes a bug in ReduceJSCreateArray, where
has_initial_map could get called when it wasn't permissible to do so.

Notes: For simplicity, in one or two places where we used to get the
target/newtarget constants from the types we now get them from
HeapConstant nodes.

Cosmetic change: rename "receiver_map" to the more accurate
"root_map" in JSNativeContextSpecialization::ExtractReceiverMaps.

Bug: chromium:939316
Change-Id: I8fd9eb50993be3d839ab9b18eeea28184c53eabf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1528435
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60301}