Add guard to for loop test clang/test/Sema/for.c (#133169)

Commit 20b7f59 includes a case that checks diagnostics for for
loops using thread locals.
This fails on platforms which do not support TLS.
This change adds guards to run this part of the test iff the feature is
supported.

Author: Ariel-Burton

clang/test/Sema/for.c

@@ -19,5 +19,8 @@ void b8 (void) { for (static struct { int i; } s;s.i;); } /* c11-warning {{decla
 void b9 (void) { for (struct { int i; } (*s)(struct { int j; } o) = 0;s;); }
 void b10(void) { for (typedef struct { int i; } (*s)(struct { int j; });;); } /* c11-warning {{non-variable declaration in 'for' loop is a C23 extension}}
                                                                                  c23-warning {{non-variable declaration in 'for' loop is incompatible with C standards before C23}} */
+
+#if __has_feature(c_thread_local)
 void b11 (void) { for (static _Thread_local struct { int i; } s;s.i;); } /* c11-warning {{declaration of non-local variable in 'for' loop is a C23 extension}}
                                                                             c23-warning {{declaration of non-local variable in 'for' loop is incompatible with C standards before C23}} */
+#endif