enhance: JavaType system

[taofengliu]

What this PR does / why we need it:

Motivation:

• OSR type recovery: during OSR compilation, a local variable of reference type is a bare load (with no metadata/attributes), and the only source of type information is the checkcast emitted by the frontend at the OSR entry; checkcast is a phase-0 JavaOp, expanded at the start of the pipeline, and its expanded form is subsequently normalized away, so dominator-chain analysis cannot recover it
• Direct use after merging multiple predecessors with the same check (diamond shape: both branches must pass check_instanceof(K, o) before reaching the merge point, and o is used directly at the merge point)
• Nested merge-of-merge (the inner merge block is a predecessor of the outer merge block)

This PR uses CFG based type sharpening to replace the current dominator tree based type sharpening.

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[NeverRaR]

LGTM

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