fix bytecode attributes for patched files

[hamzaremmal]

We should probably add a TASTY attribute in the bytecode too but as a first glance, it looks very annoying to compute in the plugin.

Closes #24161

[som-snytt]

you intend to link 24161

[hamzaremmal]

you intend to link 24161

Indeed, thanks for catching this

[sjrd]

The CI is not happy:

java.lang.IllegalArgumentException: Unsupported class file major version 12590

[sjrd]

as a first glance, it looks very annoying to compute in the plugin.

Is it? Since we can assume the .tasty file is well-formed and compiled by our version of the compiler, it should be rather straightforward:

1. Skip 4x4 = 16 bytes (magic number, major v, minor v, experimental v)
2. Read 4 bytes as toolVersionLength
3. Skip toolVersionLength bytes
4. Read 16 bytes as uuidBytes

[sjrd]

This is a very confusing name, as the "unpickler" in the compiler is the thing that actually decodes things. Consider

Suggested change

	private def unpickler(bytes: Array[Byte]): Array[Byte] = {
	private def removeScala2Pickles(bytes: Array[Byte]): Array[Byte] = {