Bump LLVM compat (#407)

Author: maleadt

Project.toml

@@ -43,7 +43,7 @@ ExprTools = "0.1"
 GPUArrays = "10.1"
 GPUCompiler = "0.26, 0.27"
 KernelAbstractions = "0.9.1"
-LLVM = "7.2, 8"
+LLVM = "7.2, 8, 9"
 LLVMDowngrader_jll = "0.3"
 ObjectFile = "0.4"
 ObjectiveC = "2.1, 3"