[analyzer] Engine: fix crash with SEH __leave keyword

MSVC has a `try-except` statement.
This statement could containt a `__leave` keyword, which is similar to
`goto` to the end of the try block. The semantic of this keyword is not
implemented.

We should at least parse such code without crashing.

https://docs.microsoft.com/en-us/cpp/cpp/try-except-statement?view=msvc-160

Patch By: AbbasSabra!

Reviewed By: steakhal

Differential Revision: https://reviews.llvm.org/D102280

clang/lib/StaticAnalyzer/Core/CoreEngine.cpp

@@ -349,6 +349,7 @@ void CoreEngine::HandleBlockExit(const CFGBlock * B, ExplodedNode *Pred) {
         HandleBranch(cast<ForStmt>(Term)->getCond(), Term, B, Pred);
         return;
 
+      case Stmt::SEHLeaveStmtClass:
       case Stmt::ContinueStmtClass:
       case Stmt::BreakStmtClass:
       case Stmt::GotoStmtClass:

clang/test/Analysis/ms-seh.cpp

@@ -0,0 +1,13 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,debug.ExprInspection -triple x86_64-pc-windows-msvc19.11.0 -fms-extensions -verify %s
+
+void clang_analyzer_warnIfReached();
+int filter();
+
+void try_except_leave() {
+  __try {
+    __leave;                        // no-crash
+    clang_analyzer_warnIfReached(); // no-warning
+  } __except (filter()) {
+  }
+  clang_analyzer_warnIfReached(); // expected-warning{{REACHABLE}}
+}