The classes are all generated; the actual bug is on line 631 of make/jdk/src/classes/build/tools/intpoly/FieldGen.java.

.../jdk/build/macosx-aarch64-server-release/support/gensrc/java.base/sun/security/util/math/intpoly/IntegerPolynomial25519.java:39: warning: [lossy-conversions] Shifting int by 38 bits is equivalent to shifting by 6 bits
    private static final int LIMB_MASK = -1 >>> (64 - BITS_PER_LIMB);
                                                ^
error: warnings found and -Werror specified
.../jdk/build/macosx-aarch64-server-release/support/gensrc/java.base/sun/security/util/math/intpoly/IntegerPolynomialP256.java:39: warning: [lossy-conversions] Shifting int by 38 bits is equivalent to shifting by 6 bits
    private static final int LIMB_MASK = -1 >>> (64 - BITS_PER_LIMB);
                                                ^
.../jdk/build/macosx-aarch64-server-release/support/gensrc/java.base/sun/security/util/math/intpoly/IntegerPolynomialP384.java:39: warning: [lossy-conversions] Shifting int by 36 bits is equivalent to shifting by 4 bits
    private static final int LIMB_MASK = -1 >>> (64 - BITS_PER_LIMB);
                                                ^
.../jdk/build/macosx-aarch64-server-release/support/gensrc/java.base/sun/security/util/math/intpoly/IntegerPolynomialP521.java:39: warning: [lossy-conversions] Shifting int by 36 bits is equivalent to shifting by 4 bits
    private static final int LIMB_MASK = -1 >>> (64 - BITS_PER_LIMB);
                                                ^
.../jdk/build/macosx-aarch64-server-release/support/gensrc/java.base/sun/security/util/math/intpoly/P256OrderField.java:39: warning: [lossy-conversions] Shifting int by 38 bits is equivalent to shifting by 6 bits
    private static final int LIMB_MASK = -1 >>> (64 - BITS_PER_LIMB);
                                                ^
.../jdk/build/macosx-aarch64-server-release/support/gensrc/java.base/sun/security/util/math/intpoly/P384OrderField.java:39: warning: [lossy-conversions] Shifting int by 36 bits is equivalent to shifting by 4 bits
    private static final int LIMB_MASK = -1 >>> (64 - BITS_PER_LIMB);
                                                ^
.../jdk/build/macosx-aarch64-server-release/support/gensrc/java.base/sun/security/util/math/intpoly/P521OrderField.java:39: warning: [lossy-conversions] Shifting int by 36 bits is equivalent to shifting by 4 bits
    private static final int LIMB_MASK = -1 >>> (64 - BITS_PER_LIMB);
                                                ^
.../jdk/build/macosx-aarch64-server-release/support/gensrc/java.base/sun/security/util/math/intpoly/Curve25519OrderField.java:39: warning: [lossy-conversions] Shifting int by 38 bits is equivalent to shifting by 6 bits
    private static final int LIMB_MASK = -1 >>> (64 - BITS_PER_LIMB);
                                                ^
.../jdk/build/macosx-aarch64-server-release/support/gensrc/java.base/sun/security/util/math/intpoly/Curve448OrderField.java:39: warning: [lossy-conversions] Shifting int by 36 bits is equivalent to shifting by 4 bits
    private static final int LIMB_MASK = -1 >>> (64 - BITS_PER_LIMB);