[CodeGen][TailDuplicator] Don't duplicate blocks with INLINEASM_BR

Tail duplication of a block with an INLINEASM_BR may result in a PHI
node on the indirect branch. This is okay, but it also introduces a copy
for that PHI node *after* the INLINEASM_BR, which is not okay.

See: https://github.com/ClangBuiltLinux/linux/issues/1125

Differential Revision: https://reviews.llvm.org/D88823