[llvm] Reduce ComplexDeinterleavingPass.h includes

Remove the unnecessary `"llvm/IR/PatternMatch.h"` include directive from
`ComplexDeinterleavingPass.h` and move it to the corresponding source
file.

Add missing includes that were transitively included by this header to 3
other source files.

This reduces the total number of preprocessing tokens across the LLVM
source files in `lib` from (roughly) 1,964,876,961 to 1,935,091,611 - a
reduction of ~1.52%. This should result in a small improvement in
compilation time.