PPC/s390: [compiler] Drive optimizations with feedback vector (reland)

Port 24b7026d

Original Commit Message:

    For interpreted functions, use the optimized code slot in the feedback
    vector to store an optimization marker (optimize/in optimization queue)
    rather than changing the JSFunction's code object. Then, adapt the
    self-healing mechanism to also dispatch based on this optimization
    marker. Similarly, replace SFI marking with optimization marker checks
    in CompileLazy.

    This allows JSFunctions to share optimization information (replacing
    shared function marking) without leaking this information across native
    contexts. Non I+TF functions (asm.js or --no-turbo) use a
    CheckOptimizationMarker shim which generalises the old
    CompileOptimized/InOptimizationQueue builtins and also checks the same
    optimization marker as CompileLazy and InterpreterEntryTrampoline.

    This is a reland of https://chromium-review.googlesource.com/c/509716

R=leszeks@chromium.org, joransiu@ca.ibm.com, bjaideep@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Review-Url: https://codereview.chromium.org/2947903002
Cr-Commit-Position: refs/heads/master@{#46109}