RFR: 8355235: Clean out old versions from Tools.gmk

[Mikael Vidstedt]

Traditionally, when upgrading the versions of the components (gcc, binutils, etc.) in Tools.gmk, the old versions/definitions have been preserved. The list is now starting to be on the long side, it's unlikely that anybody would be using anything but the latest/default version, and if they do it is possible to get it from the source/version history.

Let's clean out the old version information, leaving only the latest/default.

Testing: tier1, manually built devkits for `x86_64-linux-gnu-to-{x86_64,aarch64,ppc64le,riscv64,s390x}-linux-gnu` and then built the JDK using those devkits.

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Commit messages:
 - 8355235: Clean out old versions from Tools.gmk

Changes: https://git.openjdk.org/jdk/pull/24784/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24784&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8355235
  Stats: 120 lines in 1 file changed: 13 ins; 93 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/24784.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24784/head:pull/24784

PR: https://git.openjdk.org/jdk/pull/24784