[riscv-port] RFR: 8280683: riscv: Remove uses of long and unsigned long

[Yadong Wang]

The riscv port should follow https://bugs.openjdk.java.net/browse/JDK-8248404, for the same reason of:

In many cases the RISCV64 back end uses long and unsigned long types. These types don't work on LLP64 systems (such as Windows) and should be replaced either by int64_t or jlong, as appropriate.


Hotspot/jdk tier1 passed on the unmatched board. And all jtreg tests have been tested on Qemu without new failures.

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Commit messages:
 - 8280683: riscv: Remove uses of long and unsigned long

Changes: https://git.openjdk.java.net/riscv-port/pull/55/files
 Webrev: https://webrevs.openjdk.java.net/?repo=riscv-port&pr=55&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8280683
  Stats: 44 lines in 5 files changed: 13 ins; 19 del; 12 mod
  Patch: https://git.openjdk.java.net/riscv-port/pull/55.diff
  Fetch: git fetch https://git.openjdk.java.net/riscv-port pull/55/head:pull/55

PR: https://git.openjdk.java.net/riscv-port/pull/55