Fixes #24233: Remove misleading JDK compatibility hint for TASTy errors

[Bbn08]

Fix misleading JDK compatibility error message for TASTy version mismatches
Fixes #24233

Description

When the compiler encounters a TASTy version mismatch (e.g., attempting to read a TASTy file produced by a newer compiler version like 3.7.1 with compiler 3.3.6), it throws an UnpickleException. The error handling code in ClassfileParser and ClassfileTastyUUIDParser was catching this as a generic RuntimeException and appending a misleading message suggesting to "check the JDK compatibility of your Scala version."

This message was confusing because:

The error is about TASTy format versions (majorVersion: 28), not Java classfile versions
The JDK version suggestion is irrelevant to TASTy compatibility issues

Changes Made

• Modified exception handlers in ClassfileParser.scala and ClassfileTastyUUIDParser.scala
• Added pattern matching to detect UnpickleException specifically
• Suppress JDK compatibility hint for TASTy unpickling errors
• Preserve the hint for actual classfile version issues

Example

Before:

class file ... is broken (version 52.0),
  please check the JDK compatibility of your Scala version (3.3.6),
  reading aborted with class dotty.tools.tasty.UnpickleException:
  TASTy signature has wrong version...

After:

class file ... is broken,
  reading aborted with class dotty.tools.tasty.UnpickleException:
  TASTy signature has wrong version...

The UnpickleException message already contains clear information about the TASTy version mismatch, making the JDK hint unnecessary and confusing.

Testing

• Manually verified code correctness through inspection
• Changes are minimal and focused on error message formatting
• No functional changes to compilation logic

[Bbn08]

Hi!

Some CI checks (test-scala3-compiler-nonbootstrapped and related jobs) keep getting cancelled due to GitHub Actions infrastructure issues:

• "The job was not acquired by Runner of type hosted even after multiple attempts"
• "Internal server error"

I've tried triggering re-runs by pushing new commits, but the same infrastructure errors keep occurring.

Could a maintainer please click Re-run cancelled jobs when you get a chance? Thank you!

[tgodzik]

LGTM!