hg: amber/amber: improve error messages for field instance declarations in records

[vicente.romero at oracle.com]

Changeset: 42044a52efbf
Author:    vromero
Date:      2019-10-30 22:18 -0400
URL:       https://hg.openjdk.java.net/amber/amber/rev/42044a52efbf

improve error messages for field instance declarations in records

! src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java
! test/langtools/tools/javac/diags/examples/RecordsCanNotDeclareInstanceFields.java
! test/langtools/tools/javac/records/BadRecord.out