[TVMScript] Prevent bool to int conversion in T.Assert condition

[Lunderberg]

Previously, while literal True and False values were converted to tvm::Bool instances, constant-foldable expressions (e.g. 0 == 1) would be evaluated to True, but were then passed directly to the FFI. Because the FFI uses the same representation for integer and boolean values, the conversion to PrimExpr resulted in a tvm::Integer instead of tvm::Bool.

This commit converts the argument of T.Assert to a tvm::Bool before calling the FFI, avoiding the ambiguity. In addition, the AssertStmt constructor now validates the datatype of the condition, to prevent it from re-occurring.

This was first caught in the unit test test_debug_info.py::test_llvm_ir_debug_info, which failed validation on some versions of LLVM due to the use of i32 as the condition of an assert.

[tvm-bot]

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• cc @Hzfengsy, @junrushao, @shingjan _{See #10317 for details}

_{Generated by tvm-bot}

[junrushao]

LGTM!

[Lunderberg]

Rebased onto #14950, so CI can use its bugfix.