JIT: Defer fgSetOptions until after 2nd-pass EH removal

[AndyAyersMS]

The JIT will sometimes commit to fully-interruptible GC too early. Wait until we've had a second chance to remove EH regions.

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[AndyAyersMS]

I was hoping we could wait even longer, until after the optimization passes, but the zero init suppression logic depends on the GC mode.

This helps fix some regressions from #128541.

@EgorBo PTAL
fyi @dotnet/jit-contrib

[Copilot]

Pull request overview

This PR changes the JIT compilation pipeline ordering so fgSetOptions() (which commits to codegen choices like fully-interruptible GC and frame-pointer requirements) runs later, after additional post-morph EH cleanup has had a chance to remove empty EH regions.

Changes:

• Removed the early fgSetOptions() call from the post-morph phase.
• Added fgSetOptions() after the second-pass empty-EH removal / post-morph flow work, just before MD array morphing.