RFR: 8299608: Add Register + imm32 orq to x86_64 assembler

[Erik Österlund]

The current x86_64 orq Register + imm32 uses emit_arith, which is rather clever and checks if it can use imm8 instead. However, sometimes you really want it to be imm32 regardless, for example if you are going to patch the code. Such functionality should be added.

Since there seems to be a precedent distinguishing this with testl_imm32(Register, imm32) vs testl(Register, imm32), my proposed patch similarly adds an orq_imm32 that uses emit_arith_imm32.

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Commit messages:
 - 8299608: Add Register + imm32 orq to x86_64 assembler

Changes: https://git.openjdk.org/jdk/pull/11850/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11850&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8299608
  Stats: 6 lines in 2 files changed: 6 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/11850.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11850/head:pull/11850

PR: https://git.openjdk.org/jdk/pull/11850