tools/javac/parser/JavacParserTest.java fails with "IOException failed: java.lang.RuntimeException: Unexpected AST"

The following test fails in the JDK16 CI:

tools/javac/parser/JavacParserTest.java

Here's a snippet from the log file:

testDeepNestingNoClose: OK
testCompDeclVarType: OK
Test void JavacParserTest.testErrorRecoveryClassNotBrace() throws java.io.IOException failed: java.lang.RuntimeException: Unexpected AST, got:
package t;

class Test {
    String.<error> <error>;
    
    class <error> {
    }
    
    class <error> {
    }
    
    class A {
    }
    
    public class B {
    }
}
testCaseBodyStatements: OK
testCorrectWildcardPositions2: OK
testMissingParenthesisError: OK
testMissingExponent: OK
testCompoundAssignment: OK
testCorrectWildcardPositions4: OK
testWrongFirstToken: OK
Passed: 45, Failed 1
result: Failed. Execution failed: `main' threw exception: java.lang.RuntimeException: Tests failed: 1


test result: Failed. Execution failed: `main' threw exception: java.lang.RuntimeException: Tests failed: 1

Since this is a Tier1 failure, I'm starting this bug as a P2.