git: openjdk/loom: fibers: Remove the now-unused oopMapStubGenerator

[duke]

Changeset: c4c40afb
Author:    Ron Pressler <ron.pressler at oracle.com>
Date:      2022-02-09 13:24:21 +0000
URL:       https://git.openjdk.java.net/loom/commit/c4c40afbf7162f5f6d47e279d401b498f24c2cfa

Remove the now-unused oopMapStubGenerator

- src/hotspot/cpu/x86/oopMapStubGenerator_x86.cpp
! src/hotspot/share/compiler/oopMap.cpp
- src/hotspot/share/compiler/oopMapStubGenerator.hpp