Report illegal tokens in the Yul parser.

Author: chriseth

libyul/AsmParser.cpp

@@ -327,6 +327,9 @@ variant<Literal, Identifier> Parser::parseLiteralOrIdentifier()
 	case Token::HexStringLiteral:
 		fatalParserError(3772_error, "Hex literals are not valid in this context.");
 		break;
+	case Token::Illegal:
+		fatalParserError(1465_error, "Illegal token: " + to_string(m_scanner->currentError()));
+		break;
 	default:
 		fatalParserError(1856_error, "Literal or identifier expected.");
 	}

test/libsolidity/syntaxTests/inlineAssembly/invalid/invalid_number.sol

@@ -6,4 +6,4 @@ contract C {
   }
 }
 // ----
-// ParserError 1856: (72-73): Literal or identifier expected.
+// ParserError 1465: (72-73): Illegal token: Octal numbers not allowed.

test/libyul/yulSyntaxTests/invalid/unicode_comment_direction_override.sol

@@ -3,4 +3,4 @@
     // underflow ‬
 }
 // ----
-// ParserError 1856: (19-32): Literal or identifier expected.
+// ParserError 1465: (19-32): Unicode direction override underflow in comment or string literal.

test/libyul/yulSyntaxTests/invalid/unicode_string_direction_override.sol

@@ -3,4 +3,4 @@
     let s := unicode"underflow ‬";
 }
 // ----
-// ParserError 1856: (35-47): Literal or identifier expected.
+// ParserError 1465: (35-47): Invalid character in string.