RFR: 8348182: Remove DONT_USE_PRECOMPILED_HEADER

[Stefan Karlsson]

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 turn off and therefore we don't need to removed the include lines.

I propose that we get rid of DONT_USE_PRECOMPILED_HEADER.

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Commit messages:
 - 8348182: Remove DONT_USE_PRECOMPILED_HEADER

Changes: https://git.openjdk.org/jdk/pull/23211/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23211&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8348182
  Stats: 10 lines in 2 files changed: 0 ins; 9 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/23211.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23211/head:pull/23211

PR: https://git.openjdk.org/jdk/pull/23211