Add test cases for variable definitions inside for-init and condition…

… statements

Interpreter/execute-stmts.cpp fails with:
```
i = 2
i = 5
i = 5
i = 5
j = 4
error: Parsing failed.
error: Parsing failed.

error: 'expected-error' diagnostics seen but not expected:
  Line 1: redefinition of 'i'
  Line 1: redefinition of 'i'
error: 'expected-note' diagnostics seen but not expected:
  Line 1: previous definition is here
  Line 1: previous definition is here
```

clang/test/Interpreter/execute-stmts.cpp

@@ -9,6 +9,8 @@
 //CODEGEN-CHECK-COUNT-2: define internal void @__stmts__
 //CODEGEN-CHECK-NOT: define internal void @__stmts__
 
+// New tests fail right now
+// XFAIL: *
 
 extern "C" int printf(const char*,...);
 
@@ -41,3 +43,9 @@ for (; i > 4; --i) { printf("i = %d\n", i); };
 
 int j = i; printf("j = %d\n", j);
 // CHECK-NEXT: j = 4
+
+if (int i = j) printf("i = %d\n", i);
+// CHECK-NEXT: i = 4
+
+for (int i = j; i > 3; --i) printf("i = %d\n", i);
+// CHECK-NEXT: i = 4