[jdk16u] RFR: 8259619: C1: 3-arg StubAssembler::call_RT stack-use condition is incorrect

[Tobias Hartmann]

Backport of [JDK-8259619](https://bugs.openjdk.java.net/browse/JDK-8259619). Applies cleanly.

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Commit messages:
 - 8259619: C1: 3-arg StubAssembler::call_RT stack-use condition is incorrect

Changes: https://git.openjdk.java.net/jdk16u/pull/12/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk16u&pr=12&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259619
  Stats: 4 lines in 2 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk16u/pull/12.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16u pull/12/head:pull/12

PR: https://git.openjdk.java.net/jdk16u/pull/12