[llvm] [MC] Increase asm-macro-max-nesting-depth default to 100 (PR #218455)

[Sam Elliott via llvm-commits]

lenary wrote:

I don't understand why we need a new testcase (`default-depth.s`) rather than updating the old one (`max-depth.s`). They have significant overlap.

https://github.com/llvm/llvm-project/pull/218455