[clang][DebugInfo][test] Move debug-info tests from CodeGenCXX to DebugInfo directory (#154538)

This patch works towards consolidating all Clang debug-info into the
`clang/test/DebugInfo` directory
(https://discourse.llvm.org/t/clang-test-location-of-clang-debug-info-tests/87958).

Here we move only the `clang/test/CodeGenCXX` tests. I created a `CXX`
subdirectory for now because many of the tests I checked actually did
seem C++-specific. There is probably overlap between the `Generic` and
`CXX` subdirectory, but I haven't gone through and audited them all.

The list of files i came up with is:
1. searched for anything with `*debug-info*` in the filename
2. searched for occurrences of `debug-info-kind` in the tests

There's a couple of tests in `clang/test/CodeGenCXX` that still set
`-debug-info-kind`. They probably don't need to do that, but I'm not
changing that as part of this PR.

clang/test/CodeGenCXX/debug-info-class-limited.test

@@ -1 +0,0 @@
-RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited %S/Inputs/debug-info-class-limited.cpp -o - | FileCheck %S/Inputs/debug-info-class-limited.cpp

clang/test/DebugInfo/CXX/anon-union-vars.cpp

@@ -46,7 +46,7 @@ void instantiate(int x) {
 
 // CHECK: !DIGlobalVariable(name: "c",{{.*}} file: [[FILE:.*]], line: 6,{{.*}} isLocal: true, isDefinition: true
 // CHECK: !DIGlobalVariable(name: "d",{{.*}} file: [[FILE]], line: 6,{{.*}} isLocal: true, isDefinition: true
-// CHECK: [[FILE]] = !DIFile(filename: "{{.*}}debug-info-anon-union-vars.cpp",
+// CHECK: [[FILE]] = !DIFile(filename: "{{.*}}anon-union-vars.cpp",
 // CHECK: !DIGlobalVariable(name: "a",{{.*}} file: [[FILE]], line: 6,{{.*}} isLocal: true, isDefinition: true
 // CHECK: !DIGlobalVariable(name: "b",{{.*}} file: [[FILE]], line: 6,{{.*}} isLocal: true, isDefinition: true
 // CHECK: !DIGlobalVariable(name: "result", {{.*}} isLocal: false, isDefinition: true

clang/test/DebugInfo/CXX/class-limited-plugin.test

@@ -1,2 +1,2 @@
-RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited -o - -load %llvmshlibdir/PrintFunctionNames%pluginext -add-plugin print-fns %S/Inputs/debug-info-class-limited.cpp 2>&1 | FileCheck %S/Inputs/debug-info-class-limited.cpp
+RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited -o - -load %llvmshlibdir/PrintFunctionNames%pluginext -add-plugin print-fns %S/Inputs/class-limited.cpp 2>&1 | FileCheck %S/Inputs/class-limited.cpp
 REQUIRES: plugins, examples

clang/test/DebugInfo/CXX/class-limited.test

@@ -0,0 +1 @@
+RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited %S/Inputs/class-limited.cpp -o - | FileCheck %S/Inputs/class-limited.cpp

clang/test/DebugInfo/CXX/function-context.cpp

@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited -triple x86_64-pc-linux-gnu %s -fdebug-compilation-dir=%S \
-// RUN:     -dwarf-version=5 -main-file-name debug-info-function-context.cpp  -o - | FileCheck %s
+// RUN:     -dwarf-version=5 -main-file-name function-context.cpp  -o - | FileCheck %s
 
 struct C {
   void member_function();

clang/test/DebugInfo/CXX/lambda-expressions.cpp

@@ -21,7 +21,7 @@ int d(int x) { D y[10]; return [x,y] { return y[x].x; }(); }
 // CHECK-SAME:              line: [[VAR_LINE:[0-9]+]]
 // CHECK-SAME:              type: ![[VAR_T:[0-9]+]]
 
-// CHECK: [[FILE:.*]] = !DIFile(filename: "{{.*}}debug-lambda-expressions.cpp",
+// CHECK: [[FILE:.*]] = !DIFile(filename: "{{.*}}lambda-expressions.cpp",
 
 // CVAR:
 // CHECK: !DIGlobalVariable(name: "cvar"