Add bindings for LLVMConstGEP2, LLVMAddAlias2, LLVMBuildLoad2, LLVMBuildInvoke2, LLVMBuildGEP2, LLVMBuildInBoundsGEP2, LLVMBuildStructGEP2, LLVMBuildPtrDiff2 and use these in tests.
Add bindings for LLVMConstGEP2, LLVMAddAlias2, LLVMBuildLoad2, LLVMBuildInvoke2, LLVMBuildGEP2, LLVMBuildInBoundsGEP2, LLVMBuildStructGEP2, LLVMBuildPtrDiff2 and use these in tests.