RFR: 8278037: Removed PPC32 dead code in opConvert

[Jie Fu]

On Wed, 1 Dec 2021 03:13:38 GMT, Ao Qi <aoqi at openjdk.org> wrote:

> `_tmp1` and `_tmp2` were [removed](https://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/faaed259df37#l13.173) in [JDK-8160245](https://bugs.openjdk.java.net/browse/JDK-8160245), but they are still used.
> 
> This should cause a build error. I don't have a ppc32 machine for the test. It's also not found at https://builds.shipilev.net. Is ppc32 a supported compiler1 platform?

It looks reasonable to me.

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Marked as reviewed by jiefu (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6625