[GlobalISel] Propagate PCSections metadata to MachineInstr

Propagate (most) PC sections metadata to MachineInstr when GlobalISel is
doing instruction selection.

This change results in support for architectures using GlobalISel (such
as -O0 with AArch64). Not all instructions may be supported yet, and
requires further target-specific handling (such as done for AArch64
pseudo-atomics). Expanding supported instructions is planned on a
case-by-case basis and new use cases for PC sections metadata.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D130886