[Test] Don't generate throws Exception on methods of generated tests

This is needed to reduce the size of generated test files, which started
 to exceed default IDE limit
Also update some (mostly old) test utilities to remove exceptions from
 java signatures

generators/test-generator/tests/org/jetbrains/kotlin/generators/MethodGenerator.kt

@@ -11,7 +11,7 @@ import org.jetbrains.kotlin.utils.Printer
 abstract class MethodGenerator<in T : MethodModel> {
     companion object {
         fun generateDefaultSignature(method: MethodModel, p: Printer) {
-            p.print("public void ${method.name}() throws Exception")
+            p.print("public void ${method.name}()")
         }
     }