[riscv-port-jdk17u:riscv-port] RFR: 8294083: RISC-V: Minimal build failed with --disable-precompiled-headers

[Gui Cao]

Please review this backport to riscv-port-jdk17u.
Backport of [JDK-8294083](https://bugs.openjdk.org/browse/JDK-8294083). 
Compared to the original patch, the addition of including the corresponding header (gc/shared/collectedHeap.hpp) fix the invalid use of incomplete type 'class CollectedHeap' as follows:

=== Output from failing command(s) repeated here ===
* For target hotspot_variant-minimal_libjvm_objs_c1_Runtime1_riscv.o:

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Commit messages:
 - backport JDK-8294083

Changes: https://git.openjdk.org/riscv-port-jdk17u/pull/6/files
 Webrev: https://webrevs.openjdk.org/?repo=riscv-port-jdk17u&pr=6&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294083
  Stats: 2 lines in 2 files changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/riscv-port-jdk17u/pull/6.diff
  Fetch: git fetch https://git.openjdk.org/riscv-port-jdk17u pull/6/head:pull/6

PR: https://git.openjdk.org/riscv-port-jdk17u/pull/6