swift

7e33e554 - SIL: a few changes regarding access to a GlobalVariable's static initializer instructions

SIL: a few changes regarding access to a GlobalVariable's static initializer instructions * add `GlobalVariable.staticInitializerInstructions` to access all initializer instructions of a global * implement `GlobalVariable.staticInitValue` with `GlobalVariable.staticInitializerInstructions` * this requires that `InstructionList.reversed()` works without accessing the parent block of the iterator instruction * allow `Context.erase(instruction:)` to delete instructions from a global's initializer list, which means to handle the case where a deleted instruction has no parent function.