Refactor REPL tests: use empty line instead of "null"

compiler/testData/repl/analyzeErrors.repl

@@ -1,5 +1,4 @@
 >>> fun foo() = 765
-null
 >>> foo(1)
 ERROR: /line2.kts: (1, 5) Too many arguments for internal final fun foo(): kotlin.Int defined in <script>
 >>> foo()

compiler/testData/repl/empty.repl

@@ -1,8 +1,6 @@
 >>>
-null
 >>> 101
 101
 >>>
-null
 >>> 102
 102

compiler/testData/repl/evaluationErrors.repl

@@ -1,6 +1,5 @@
 >>> throw Exception("hi there")
 substring: Exception: hi there
 >>> fun foo() = 2
-null
 >>> foo()
 2

compiler/testData/repl/function.repl

@@ -1,4 +1,3 @@
 >>> fun foo() = 2
-null
 >>> foo()
 2

compiler/testData/repl/functionOverloadResolution.repl

@@ -1,6 +1,4 @@
 >>> fun foo() = 10
-null
 >>> fun foo() = 11
-null
 >>> foo()
 11

compiler/testData/repl/functionOverloadResolutionAnyBeatsString.repl

@@ -1,6 +1,4 @@
 >>> fun foo(s: String) = "string"
-null
 >>> fun foo(a: Any) = "any"
-null
 >>> foo("a")
 any

compiler/testData/repl/functionReferencesPrev.repl

@@ -1,6 +1,4 @@
 >>> val x = 1
-null
 >>> fun add1(y: Int) = x + y
-null
 >>> add1(999999)
 1000000

compiler/testData/repl/imports.repl

@@ -1,6 +1,4 @@
 >>> import java.io.ByteArrayOutputStream
-null
 >>> val s = ByteArrayOutputStream()
-null
 >>> s.javaClass!!.getName()
 java.io.ByteArrayOutputStream

compiler/testData/repl/multiline.repl

@@ -1,6 +1,5 @@
 >>> fun clock() =
 incomplete
 >>>     12
-null
 >>> clock()
 12

compiler/testData/repl/multiline3.repl

@@ -5,6 +5,5 @@ incomplete
 >>>     2 +
 incomplete
 >>>     1
-null
 >>> get7()
 7

compiler/testData/repl/syntaxErrors.repl

@@ -2,6 +2,5 @@
 ERROR: /line1.kts: (1, 1) Expecting an element
 ERROR: /line1.kts: (1, 3) Expecting an expression
 >>> fun foo() = 98
-null
 >>> foo()
 98

compiler/tests/org/jetbrains/jet/repl/AbstractReplInterpreterTest.java

@@ -116,7 +116,7 @@ public abstract class AbstractReplInterpreterTest extends UsefulTestCase {
             else {
                 actual = lineResult.getErrorText();
             }
-            String actualString = StringUtil.convertLineSeparators(actual != null ? actual.toString() : "null").replaceFirst("\n$", "");
+            String actualString = StringUtil.convertLineSeparators(actual != null ? actual.toString() : "").replaceFirst("\n$", "");
 
             if (line.matchType == MatchType.EQUALS) {
                 Assert.assertEquals("after evaluation of: " + line.code, expected, actualString);