[clang] [Clang] skip default argument instantiation for non-defining friend declarations without specialization info to meet [dcl.fct.default] p4 (PR #113777)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

Reverted. The issue looks like the instantiation of the default argument was skipped, but without any previous error actually being produced, so it proceeded to CodeGen with invalid AST.

https://github.com/llvm/llvm-project/pull/113777