[LLVM-C] Add support for ConstantExpr in LLVMGetNumIndices and LLVMGetIndices
[LLVM-C] Add support for ConstantExpr in LLVMGetNumIndices and LLVMGetIndices

Summary:
ConstantExpr supports getIndices, but prior to this patch
LLVMGetNumIndices and LLVMGetIndices would error on them.

Reviewers: whitequark

Reviewed By: whitequark

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D52206

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@342434 91177308-0d34-0410-b5e6-96231b3b80d8

GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm