Checked Qualifier Support

[arunkumarbhattar]

Title: Add Test Suite for Backward Compatibility Syntax and Macros

Description: This PR adds a comprehensive test suite to verify the correct implementation of the alternate syntax and macros introduced for enhancing backward compatibility of Checked C code with non-Checked C compilers, as proposed in this wiki page. The test suite covers the following key aspects:

Pointer types: Test cases to validate the proper functioning of _Array, _Nt_array, and _Single qualifiers for pointer types.
Arrays: Verify that the _Checked keyword behaves as expected when a compiler does not support Checked C.
Generic types: Validate the correct functioning of the _TyArg and _TyVar macros, as well as the two-part approach for generic function definitions and generic struct definitions.
Bounds annotations: Validate the new keywords _Any, _Bounds, _Byte_count, and _Count for bounds expressions, and test cases for declarators followed by bounds expressions.
Dynamic check expressions: Test cases to ensure the correct evaluation of dynamic check expressions and their compatibility with the assert macro.
Bounds cast expressions: Validate the functioning of variadic macros for _Dynamic_bounds_cast and _Assume_bounds_cast expressions, and their correct mapping to syntax forms or C-style casts.
Where clauses: Test cases for where clauses with optional parentheses, and the proper discarding of the where clause body when Checked C is not supported.
The test suite ensures that the alternate syntax and macros introduced for backward compatibility function correctly and maintain the safety guarantees of Checked C code, improving code portability and platform compatibility.
REGRESSION SANITY*************
Clang Regression sanity tests (TARGET: check-clang):

Testing Time: 2216.67s
Unsupported : 74
Passed : 27667
Expectedly Failed: 34

CheckedC regression sanity test (TARGET: check-checkedc)
checkedc :: checkedc/tests/typechecking/pointer_types.c
Testing Time: 17.55s
Unsupported: 3
Passed : 96

Testing Time: 3170.01s
Unsupported : 734
Passed : 69511
Expectedly Failed: 193
Failed : 12

Untouched version was failing 10 test cases.
Checking the RC behind the two extra failed TCs. Mostly could be a VM issue.
REGRESSION SANITY*************

[arunkumarbhattar]

Explanation:
TypeQualifiers are defined under DeclSpec (First phase of parsing qualifiers) and QualType (2nd phase)
I have expanded TQ under DeclSpec but NOT under QualType as doing the second was rabbit hole and required major changes, due to its interweaving with 3-Bit FastMask (expanding this in size is extremely complex)

[dtarditi]

@arunkumarbhattar Is this subsumed.by PR #1199? It looks it is. If so, we should close this PR.