[clang] [clang] Track function template instantiation from definition (PR #110387)

[Younan Zhang via cfe-commits]

================
@@ -1829,7 +1831,7 @@ class DeclContext {
     /// exactly 64 bits and thus the width of NumCtorInitializers
     /// will need to be shrunk if some bit is added to NumDeclContextBitfields,
     /// NumFunctionDeclBitfields or CXXConstructorDeclBitfields.
-    uint64_t NumCtorInitializers : 17;
+    uint64_t NumCtorInitializers : 16;
----------------
zyn0217 wrote:

nit: You also need to update the attached comments
```cpp
    /// 20 bits to fit in the remaining available space.
    /// ...
```
=>
```cpp
    /// 19 bits to fit in the remaining available space.
```

https://github.com/llvm/llvm-project/pull/110387