[clangd] Get rid of delayed template parsing

Summary:
No need to pass fno-delayed-template-parsing as the opposite flag is
only passed to cc1 when abi is set to msvc. Sending as a follow-up to D73613 to
keep changes in the release branch minimal.

Reviewers: sammccall

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D73615

clang-tools-extra/clangd/unittests/HoverTests.cpp

@@ -580,9 +580,6 @@ class Foo {})cpp";
     Annotations T(Case.Code);
     TestTU TU = TestTU::withCode(T.code());
     TU.ExtraArgs.push_back("-std=c++17");
-    // FIXME: This is no longer necessary, as the default behavior is no delayed
-    // parsing in the triplet below.
-    TU.ExtraArgs.push_back("-fno-delayed-template-parsing");
     // Types might be different depending on the target triplet, we chose a
     // fixed one to make sure tests passes on different platform.
     TU.ExtraArgs.push_back("--target=x86_64-pc-linux-gnu");