[flang][msvc] Add explicit function template argument to applyLamda. NFC.

[Meinersbur]

Summary

Like in D87961, msvc has difficulties deducing the template argument. The error message is:

expr-parsers.cpp(383): error C2672: 'applyLambda': no matching overloaded function found

Explicitly pass the first template argument to help it.

This patch is part of the series to make flang compilable with MS Visual Studio http://lists.llvm.org/pipermail/flang-dev/2020-July/000448.html.

[DavidTruby]

LGTM

flang/lib/Parser/expr-parsers.cpp

template <> std::optional<Expr> Parser<Expr>::Parse(ParseState &state) {
   std::optional<Expr> result{level5Expr.Parse(state)};
   if (result) {
     auto source{result->source};
     std::function<Expr(DefinedOpName &&, Expr &&)> defBinOp{
         [&result](DefinedOpName &&op, Expr &&right) {
           return Expr{Expr::DefinedBinary(
               std::move(op), std::move(result).value(), std::move(right))};
         }};
-    auto more{
-        attempt(sourced(applyLambda(defBinOp, definedOpName, level5Expr)))};
+    auto more{attempt(
+        sourced(applyLambda<Expr>(defBinOp, definedOpName, level5Expr)))};
     while (std::optional<Expr> next{more.Parse(state)}) {
       result = std::move(next);
       result->source.ExtendToCover(source);
     }
   }
   return result;
 }