[clang] Add test for CWG1822

[Endill]

Summary

P1787: CWG1822 is resolved by specifying that the body of a lambda remains in the surrounding (function parameter) scope.
Wording: A parameter-declaration-clause P introduces a function parameter scope that includes P. <...> If P is associated with a lambda-declarator, its scope extends to the end of the compound-statement in the lambda-expression. ([basic.scope.param])

[shafik]

Thank you! LGTM

clang/test/CXX/drs/dr18xx.cpp

#if __cplusplus >= 201402L
   struct A { int &&r = 0; }; // expected-note {{default member init}}
   A a = {}; // FIXME expected-warning {{not supported}}
 
   struct B { int &&r = 0; }; // expected-error {{binds to a temporary}} expected-note {{default member init}}
   B b; // expected-note {{here}}
 #endif
 }
 
+namespace dr1822 { // dr1822: yes
+#if __cplusplus >= 201103L
+  int a;
+  auto x = [] (int a) {
+#pragma clang __debug dump a // CHECK: ParmVarDecl
+  };
+#endif
+}
+
 namespace dr1872 { // dr1872: 9
 #if __cplusplus >= 201103L
   template<typename T> struct A : T {
     constexpr int f() const { return 0; }
   };
   struct X {};
   struct Y { virtual int f() const; };
   struct Z : virtual X {};

clang/www/cxx_dr_status.html

<tr id="1821">
     <td>CD6</td>
     <td>Qualified redeclarations in a class <I>member-specification</I></td>
     <td class="none" align="center">Unknown</td>
   </tr>
   <tr id="1822">
     <td><a href="https://wg21.link/cwg1822">1822</a></td>
     <td>CD6</td>
     <td>Lookup of parameter names in <I>lambda-expression</I>s</td>
-    <td class="none" align="center">Unknown</td>
+    <td class="full" align="center">Yes</td>
   </tr>
   <tr id="1823">
     <td><a href="https://wg21.link/cwg1823">1823</a></td>
     <td>CD4</td>
     <td>String literal uniqueness in inline functions</td>
     <td class="none" align="center">Unknown</td>
   </tr>
   <tr id="1824">