Revert r325375 "[MS] Make constexpr static data members implicitly inline"

This broke Clang bootstrap on Windows, PR36453.

> This handles them exactly the same way that we handle const integral
> static data members with inline definitions, which is what MSVC does.
>
> As a follow-up, now that we have a way to mark variables inline in the
> AST, we should consider marking them implicitly inline there instead of
> only treating them as inline in CodeGen. Unfortunately, this breaks a
> lot of dllimport test cases, so that is future work for now.
>
> Fixes PR36125.

llvm-svn: 325576
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 466a5d5..fff714c 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -5857,7 +5857,7 @@
 bool ASTContext::isMSStaticDataMemberInlineDefinition(const VarDecl *VD) const {
   return getTargetInfo().getCXXABI().isMicrosoft() &&
          VD->isStaticDataMember() &&
-         (VD->getType()->isIntegralOrEnumerationType() || VD->isConstexpr()) &&
+         VD->getType()->isIntegralOrEnumerationType() &&
          !VD->getFirstDecl()->isOutOfLine() && VD->getFirstDecl()->hasInit();
 }