RFR: 8348182: Remove DONT_USE_PRECOMPILED_HEADER

[Aleksey Shipilev]

On Tue, 21 Jan 2025 12:41:13 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> Before [JDK-8347909](https://bugs.openjdk.org/browse/JDK-8347909) we had to remove the include lines in precompiled.hpp when precompiled headers were turned off. This was done by defining DONT_USE_PRECOMPILED_HEADER.
> 
> After [JDK-8347909](https://bugs.openjdk.org/browse/JDK-8347909) we simply don't include precompiled.hpp if precompiled headers are turned off and therefore we don't need to removed the include lines.
> 
> I propose that we get rid of DONT_USE_PRECOMPILED_HEADER.

I can see more `DONT_USE_PRECOMPILED_HEADER` uses in `test/hotspot/gtest`, take a look at those?

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PR Review: https://git.openjdk.org/jdk/pull/23211#pullrequestreview-2564906400