fix(tvm): canonicalize ModExp zero modulus output (TIP-871)

[yanghang8612]

Summary

• gate MODEXP zero-modulus output canonicalization behind ALLOW_TVM_OSAKA
• reset CREATE2 call return-data state behind the same Osaka gate
• add direct Osaka MODEXP tests plus a Solidity 0.8.25 VM-level reproduction for MODEXP and CREATE2 observable behavior

Motivation

Related to tronprotocol/tips#871. MODEXP currently returns empty output for an all-zero modulus even when modLen > 0; after Osaka it should return modLen zero bytes. CREATE2 also needs to match CREATE by clearing stale return-data state before execution once the Osaka behavior is active.

Testing

./gradlew :framework:test --tests org.tron.common.runtime.vm.AllowTvmOsakaTest --tests org.tron.common.runtime.vm.TvmIssueVerifierTest

[yanghang8612]

Closing to reopen a clean PR with the finalized title.