[mlir-tblgen] trim method body to empty with only spaces to avoid crash (#139568)

method body or default impl must be true empty. Even they contain only
spaces, ``mlir-tblgen`` considers they are non-empty and generates
invalid code lead to segment fault. It's very hard to debug.

```c++
    InterfaceMethod<
      ...
      /*methodBody=*/  [{ }],    // This must be true empty. Leaving a space here can lead to segment fault which is hard to figure out why
      /*defaultImpl=*/ [{
        ...
      }]
```

This PR trim spaces when method body or default implementation of
interface method is not empty. Now ``mlir-tblgen`` generates valid code
even when they contain only spaces.

---------

Co-authored-by: Fung Xie <ftse@nvidia.com>
Co-authored-by: Mehdi Amini <joker.eph@gmail.com>

0 files changed, 0 insertions, 0 deletions