[Alignment][NFC] Remove deprecated functions introduced in 10.0.0

Summary:
24 March 2020: LLVM 10.0.0 is out.
I gathered all deprecated function introduced between 9 and 10 and cleaned them up so they will be removed from 11.

> git log -p -S LLVM_ATTRIBUTE_DEPRECATED llvmorg-9.0.0..llvmorg-10.0.0

Reviewers: courbet

Subscribers: hiraditya, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77409