ra_mbe: added test for malformed token in macro invokation
ra_mbe: added test for malformed token in macro invokation

There was a panic where lexer returned None on malformed tokens.
But now we just ignore tokenization errors in mbe.

rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer