[C++20] [Modules] Support generating in-class defined function with try-catch body

See the example:

```
export module func;
class C {
public:
    void member() try {

    } catch (...) {

    }
};
```

We woudln't generate the definition for `C::member` but we should. Since
the function is non-inline in modules.

This turns out to be an oversight in parser to me. Since the try-catch
body is relatively rare, so maybe we just forgot it.

Author: ChuanqiXu9

clang/lib/Parse/ParseCXXInlineMethods.cpp

@@ -632,6 +632,11 @@ void Parser::ParseLexedMethodDef(LexedMethod &LM) {
 
     if (Tok.is(tok::eof) && Tok.getEofData() == LM.D)
       ConsumeAnyToken();
+
+    if (auto *FD = dyn_cast_or_null<FunctionDecl>(LM.D))
+      if (isa<CXXMethodDecl>(FD) ||
+          FD->isInIdentifierNamespace(Decl::IDNS_OrdinaryFriend))
+        Actions.ActOnFinishInlineFunctionDef(FD);
     return;
   }
   if (Tok.is(tok::colon)) {

clang/test/Modules/try-func-body.cppm

@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -std=c++20 %s -fexceptions -fcxx-exceptions -emit-llvm -triple %itanium_abi_triple -o - | FileCheck %s
+
+export module func;
+class C {
+public:
+    void member() try {
+
+    } catch (...) {
+
+    }
+};
+
+// CHECK: define {{.*}}@_ZNW4func1C6memberEv