Make "descriptors" not depend on intellij-core

Remove dependency on ProcessCanceledException with a hacky solution not to
break anything at the moment

core/descriptors/descriptors.iml

@@ -7,7 +7,6 @@
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
-    <orderEntry type="library" scope="PROVIDED" name="intellij-core" level="project" />
     <orderEntry type="module" module-name="util.runtime" />
     <orderEntry type="module" module-name="serialization" />
     <orderEntry type="library" exported="" name="builtins" level="project" />

core/descriptors/src/org/jetbrains/jet/lang/types/TypeSubstitutor.java

@@ -16,7 +16,6 @@
 
 package org.jetbrains.jet.lang.types;
 
-import com.intellij.openapi.progress.ProcessCanceledException;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.descriptors.TypeParameterDescriptor;
@@ -253,10 +252,11 @@ public class TypeSubstitutor {
         try {
             return o.toString();
         }
-        catch (ProcessCanceledException e) {
-            throw e;
-        }
         catch (Throwable e) {
+            if (e.getClass().getName().equals("com.intellij.openapi.progress.ProcessCanceledException")) {
+                //noinspection ConstantConditions
+                throw (RuntimeException) e;
+            }
             return "[Exception while computing toString(): " + e + "]";
         }
     }