Port c96ac82c

Original Commit Message:

    This makes stack checks in WasmCode independent of the underlying
    Isolate by loading the limit address from the WasmInstanceObject instead
    of embedding it into the instruction stream. It hence removes the last
    use of the Isolate field from WasmGraphBuilder.

    Additionally this introduces the notion of a "runtime stub" which
    represents stub code global to the NativeModule that can be directly
    called from each WasmCode in the same module. These stubs can act as
    trampolines via which Isolate-independent WasmCode can enter other V8
    builtins or runtime functions that remain Isolate-dependent. They will
    eventually replace the current "trampoline" in a NativeModule.

R=mstarzinger@chromium.org, joransiu@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=v8:7424
LOG=N

Change-Id: I5745a20133c930aecb80119e71ac1d8717e267bf
Reviewed-on: https://chromium-review.googlesource.com/1085276Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#53503}