RFR: 8305171: PPC: Should use IMA::load_resolved_indy_entry() in TIG::generate_return_entry_for()

[Richard Reingruber]

This PR replaces a sequence of assembler instructions in the interpreter with an equivalent call of `InterpreterMacroAssembler::load_resolved_indy_entry()`.

Tested hotspot tier1.

-------------

Commit messages:
 - Eliminate extra addi for array base offset
 - Use load_resolved_indy_entry() in generate_return_entry_for()

Changes: https://git.openjdk.org/jdk/pull/13226/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13226&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305171
  Stats: 13 lines in 3 files changed: 1 ins; 6 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/13226.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13226/head:pull/13226

PR: https://git.openjdk.org/jdk/pull/13226