hg: amber/amber/langtools: fixing minor bug, use asMethodType() to avoid errors if the method is generic

[vicente.romero at oracle.com]

Changeset: 59d6c4fe1750
Author:    vromero
Date:      2017-04-19 14:07 -0700
URL:       http://hg.openjdk.java.net/amber/amber/langtools/rev/59d6c4fe1750

fixing minor bug, use asMethodType() to avoid errors if the method is generic

! src/jdk.compiler/share/classes/com/sun/tools/javac/comp/ConstFold.java