[jdk18] RFR: 8272058: 25 Null pointer dereference defect groups in 4 files [v3]

[Daniel D.Daugherty]

> A small refactoring to resolve a Parfait complaint about the return value from
> `MacroAssembler::target_addr_for_insn(address insn_addr, unsigned insn)`
> on AARCH64. The logic that supports returning `nullptr` as the target addr for
> a particular instruction is moved from
> `MacroAssembler::target_addr_for_insn(address insn_addr, unsigned insn)` to
> `MacroAssembler::target_addr_for_insn_allow_null_ret(address insn_addr, unsigned insn)`.
> A couple of `target_addr_for_insn()` call sites that can tolerate a `nullptr` are
> converted to use `target_addr_for_insn_allow_null_ret()`.
> 
> This fix has been tested with Mach5 Tier[1-3].

Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:

  bulasevich CR - use NativeInstruction::is_ldrw_to_zr() instead of raw constants.

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

Changes:
  - all: https://git.openjdk.java.net/jdk18/pull/51/files
  - new: https://git.openjdk.java.net/jdk18/pull/51/files/55ef47ff..c8bbd4db

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk18&pr=51&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk18&pr=51&range=01-02

  Stats: 4 lines in 1 file changed: 0 ins; 2 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk18/pull/51.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk18 pull/51/head:pull/51

PR: https://git.openjdk.java.net/jdk18/pull/51