🌲 Disabling failing Linux tests for rebranch visibility

[etcwilde]

Disabling on rebranch:

• Frontend/dependencies-fine.swift
• DebugInfo/BridgingHeaderPCH.swift
• DebugInfo/ClangModuleBreadcrumbs.swift

Trying to see where the rest of the toolchain build stands on Linux.

[etcwilde]

@swift-ci please smoke test

[etcwilde]

I expect failures, but macOS and Linux should both be failing during the SwiftPM build.

[beccadax]

@compnerd Could your changes in #68302 have caused Frontend/dependencies-fine.swift to start running on Linux when it previously did not? The test appears to import Objective-C code when clang is not configured to parse it, which causes a cascade of errors where clang has a really hard time understanding things like id and @class as plain C.

[compnerd]

It seems unlikely to me, the removed aspects were:

// REQUIRES: shell
// Also uses awk:
// XFAIL OS=windows

shell should be available on Linux.