[RTL][NDK] Improve RtlUnhandledExceptionFilter(2) (#8353)

- Reimplement `RtlUnhandledExceptionFilter()` by just calling
  `RtlUnhandledExceptionFilter2()`.

- Return an adequate exception filter value `EXCEPTION_CONTINUE_SEARCH`
  from `RtlUnhandledExceptionFilter2()`, instead of some random error.
  If `ExceptionCode` is `STATUS_POSSIBLE_DEADLOCK` however, return
  `EXCEPTION_CONTINUE_EXECUTION` instead, as shown by a test from Whindmar Saksit.

- The second parameter of `RtlUnhandledExceptionFilter2()` is not
  a flag, but a pointer to string `PCSTR` !
  See https://skanthak.hier-im-netz.de/download/NTDLL.H
  who is the only one online who has the correct definition,
  whose usage I've double-checked on Win7 ntdll.dll.

  This is used in the `<function_name>` slot in the displayed
  debugger message:
  ```
  *** An Access Violation occurred in <program_command_line>:<function_name>
  The instruction at <address> tried to write to a NULL pointer
  ```
  For example, see: https://community.osr.com/t/access-violation/33435

sdk/include/ndk/rtlfuncs.h

@@ -676,7 +676,7 @@ NTSYSAPI
 LONG
 NTAPI
 RtlUnhandledExceptionFilter(
-    _In_ struct _EXCEPTION_POINTERS* ExceptionInfo
+    _In_ PEXCEPTION_POINTERS ExceptionInfo
 );
 
 __analysis_noreturn

sdk/lib/rtl/exception.c

@@ -241,7 +241,7 @@ static VOID
     PEXCEPTION_RECORD ExceptionRecord = ExceptionInfo->ExceptionRecord;
     PCONTEXT ContextRecord = ExceptionInfo->ContextRecord;
 
-    /* Print a stack trace. */
+    /* Print a stack trace */
     DbgPrint("Unhandled exception\n");
     DbgPrint("ExceptionCode:    %8x\n", ExceptionRecord->ExceptionCode);
 
@@ -310,12 +310,10 @@ static VOID
  */
 LONG
 NTAPI
-RtlUnhandledExceptionFilter(IN struct _EXCEPTION_POINTERS* ExceptionInfo)
+RtlUnhandledExceptionFilter(
+    _In_ PEXCEPTION_POINTERS ExceptionInfo)
 {
-    /* This is used by the security cookie checks, and also called externally */
+    return RtlUnhandledExceptionFilter2(ExceptionInfo, "");
-    UNIMPLEMENTED;
-    PrintStackTrace(ExceptionInfo);
-    return ERROR_CALL_NOT_IMPLEMENTED;
 }
 
 /*
@@ -325,12 +323,17 @@ LONG
 NTAPI
 RtlUnhandledExceptionFilter2(
     _In_ PEXCEPTION_POINTERS ExceptionInfo,
-    _In_ ULONG Flags)
+    _In_ PCSTR Function)
 {
     /* This is used by the security cookie checks, and also called externally */
     UNIMPLEMENTED;
+    ASSERT(ExceptionInfo && ExceptionInfo->ExceptionRecord);
+
     PrintStackTrace(ExceptionInfo);
-    return ERROR_CALL_NOT_IMPLEMENTED;
+
+    if (ExceptionInfo->ExceptionRecord->ExceptionCode == STATUS_POSSIBLE_DEADLOCK)
+        return EXCEPTION_CONTINUE_EXECUTION;
+    return EXCEPTION_CONTINUE_SEARCH;
 }
 
 /*