AsmParser: Stop requiring 'name:' when it's not printed

r230877 optimized which fields are written out for `CHECK`-ability, but
apparently missed changing some of them to optional in `LLParser`.

Fixes PR22921.

llvm-svn: 232400
diff --git a/llvm/test/Assembler/mdsubprogram.ll b/llvm/test/Assembler/mdsubprogram.ll
index ff7b1fe..7447166 100644
--- a/llvm/test/Assembler/mdsubprogram.ll
+++ b/llvm/test/Assembler/mdsubprogram.ll
@@ -23,6 +23,6 @@
                    flags: DIFlagPrototyped, isOptimized: true, function: void ()* @_Z3foov,
                    templateParams: !5, declaration: !6, variables: !7)
 
-; CHECK: !9 = !MDSubprogram(name: "bar", scope: null, isLocal: false, isDefinition: true, isOptimized: false)
-!9 = !MDSubprogram(name: "bar")
+; CHECK: !9 = !MDSubprogram(scope: null, isLocal: false, isDefinition: true, isOptimized: false)
+!9 = !MDSubprogram()