IR: Drop scope from MDTemplateParameter

Follow-up to r229740, which removed `DITemplate*::getContext()` after my
upgrade script revealed that scopes are always `nullptr` for template
parameters.  This is the other shoe: drop `scope:` from
`MDTemplateParameter` and its two subclasses.  (Note: a bitcode upgrade
would be pointless, since the hierarchy hasn't been moved into place.)

llvm-svn: 229791
diff --git a/llvm/test/Assembler/mdtemplateparameter.ll b/llvm/test/Assembler/mdtemplateparameter.ll
index aef2bfd..f005c08 100644
--- a/llvm/test/Assembler/mdtemplateparameter.ll
+++ b/llvm/test/Assembler/mdtemplateparameter.ll
@@ -8,17 +8,17 @@
 !1 = distinct !{}
 ; CHECK: !1 = distinct !{}
 
-; CHECK-NEXT: !2 = !MDTemplateTypeParameter(scope: !0, name: "Ty", type: !1)
-; CHECK-NEXT: !3 = !MDTemplateTypeParameter(scope: !0, name: "", type: !1)
-!2 = !MDTemplateTypeParameter(scope: !0, name: "Ty", type: !1)
-!3 = !MDTemplateTypeParameter(scope: !0, type: !1)
-!4 = !MDTemplateTypeParameter(scope: !0, name: "", type: !1)
+; CHECK-NEXT: !2 = !MDTemplateTypeParameter(name: "Ty", type: !1)
+; CHECK-NEXT: !3 = !MDTemplateTypeParameter(name: "", type: !1)
+!2 = !MDTemplateTypeParameter(name: "Ty", type: !1)
+!3 = !MDTemplateTypeParameter(type: !1)
+!4 = !MDTemplateTypeParameter(name: "", type: !1)
 
-; CHECK-NEXT: !4 = !MDTemplateValueParameter(tag: DW_TAG_template_value_parameter, scope: !0, name: "V", type: !1, value: i32 7)
-; CHECK-NEXT: !5 = !MDTemplateValueParameter(tag: DW_TAG_template_value_parameter, scope: !0, name: "", type: !1, value: i32 7)
+; CHECK-NEXT: !4 = !MDTemplateValueParameter(tag: DW_TAG_template_value_parameter, name: "V", type: !1, value: i32 7)
+; CHECK-NEXT: !5 = !MDTemplateValueParameter(tag: DW_TAG_template_value_parameter, name: "", type: !1, value: i32 7)
 !5 = !MDTemplateValueParameter(tag: DW_TAG_template_value_parameter,
-                               scope: !0, name: "V", type: !1, value: i32 7)
+                               name: "V", type: !1, value: i32 7)
 !6 = !MDTemplateValueParameter(tag: DW_TAG_template_value_parameter,
-                               scope: !0, type: !1, value: i32 7)
+                               type: !1, value: i32 7)
 !7 = !MDTemplateValueParameter(tag: DW_TAG_template_value_parameter,
-                               scope: !0, name: "", type: !1, value: i32 7)
+                               name: "", type: !1, value: i32 7)