[clang] [clang] Extract in-memory module cache writes from `ASTWriter` (PR #190062)

[Jan Svoboda via cfe-commits]

jansvoboda11 wrote:

@lei137 Thanks for the heads-up, I'll consider reverting. Could you please provide complete output of the failing commands in each test? Between LIT truncating the output and me not being to able to get my hands on an AIX machine, this will be difficult to debug otherwise.

https://github.com/llvm/llvm-project/pull/190062