reland "[DebugInfo] Support to emit debugInfo for extern variables"

Commit d77ae1552fc21a9f3877f3ed7e13d631f517c825
("[DebugInfo] Support to emit debugInfo for extern variables")
added deebugInfo for extern variables for BPF target.
The commit is reverted by 891e25b02d760d0de18c7d46947913b3166047e7
as the committed tests using %clang instead of %clang_cc1 causing
test failed in certain scenarios as reported by Reid Kleckner.

This patch fixed the tests by using %clang_cc1.

Differential Revision: https://reviews.llvm.org/D71818
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index d918551..9f5811d 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -640,13 +640,14 @@
 
 DIGlobalVariableExpression *DIBuilder::createGlobalVariableExpression(
     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
-    unsigned LineNumber, DIType *Ty, bool isLocalToUnit, DIExpression *Expr,
+    unsigned LineNumber, DIType *Ty, bool isLocalToUnit,
+    bool isDefined, DIExpression *Expr,
     MDNode *Decl, MDTuple *templateParams, uint32_t AlignInBits) {
   checkGlobalVariableScope(Context);
 
   auto *GV = DIGlobalVariable::getDistinct(
       VMContext, cast_or_null<DIScope>(Context), Name, LinkageName, F,
-      LineNumber, Ty, isLocalToUnit, true, cast_or_null<DIDerivedType>(Decl),
+      LineNumber, Ty, isLocalToUnit, isDefined, cast_or_null<DIDerivedType>(Decl),
       templateParams, AlignInBits);
   if (!Expr)
     Expr = createExpression();