[mlir][Transforms] Report all allowPatternRollback violations as fatal errors (#148416)

Report all `allowPatternRollback` API violations as fatal errors. If
violated, the IR is potentially in an invalid/inconsistent state from
which the driver cannot recover.

Author: matthias-springer

mlir/lib/Transforms/Utils/DialectConversion.cpp

@@ -2266,9 +2266,8 @@ OperationLegalizer::legalizeWithPattern(Operation *op,
     appliedPatterns.erase(&pattern);
     if (failed(result)) {
       if (!rewriterImpl.config.allowPatternRollback)
-        op->emitError("pattern '")
-            << pattern.getDebugName()
-            << "' produced IR that could not be legalized";
+        llvm::report_fatal_error("pattern '" + pattern.getDebugName() +
+                                 "' produced IR that could not be legalized");
       rewriterImpl.resetState(curState, pattern.getDebugName());
     }
     if (config.listener)