[clang] [OpenMP][Clang] Handle unsupported inscan modifier for generic types (PR #79431)

[Animesh Kumar via cfe-commits]

================
@@ -12,28 +12,6 @@
 
 void foo() {}
 
-template <class T>
----------------
animeshk-amd wrote:

The test was passing because the `for` directive at line:18 is used outside a parallel region, in which case the compiler wasn't crashing. Contrary to what would happen when used within a parallel region. 
Since the `scan` directive currently doesn't support templates, within or without a parallel region, I transferred this test to the scan_messages.cpp line:87 with expected errors.

https://github.com/llvm/llvm-project/pull/79431