Add test for obsolete recovery case (semi-finished extension)

^KT-7405 Obsolete

compiler/testData/psi/recovery/UnfinishedExtension.kt

@@ -0,0 +1,4 @@
+fun Any.
+
+fun goodFunction() {
+}

compiler/testData/psi/recovery/UnfinishedExtension.txt

@@ -0,0 +1,28 @@
+KtFile: UnfinishedExtension.kt
+  PACKAGE_DIRECTIVE
+    <empty list>
+  IMPORT_LIST
+    <empty list>
+  FUN
+    PsiElement(fun)('fun')
+    PsiWhiteSpace(' ')
+    TYPE_REFERENCE
+      USER_TYPE
+        REFERENCE_EXPRESSION
+          PsiElement(IDENTIFIER)('Any')
+    PsiElement(DOT)('.')
+    PsiErrorElement:Expecting function name
+      <empty list>
+  PsiWhiteSpace('\n\n')
+  FUN
+    PsiElement(fun)('fun')
+    PsiWhiteSpace(' ')
+    PsiElement(IDENTIFIER)('goodFunction')
+    VALUE_PARAMETER_LIST
+      PsiElement(LPAR)('(')
+      PsiElement(RPAR)(')')
+    PsiWhiteSpace(' ')
+    BLOCK
+      PsiElement(LBRACE)('{')
+      PsiWhiteSpace('\n')
+      PsiElement(RBRACE)('}')

compiler/tests/org/jetbrains/kotlin/parsing/ParsingTestGenerated.java

@@ -2173,6 +2173,11 @@ public class ParsingTestGenerated extends AbstractParsingTest {
                 runTest("compiler/testData/psi/recovery/SameLineStatementRecovery.kt");
             }
 
+            @TestMetadata("UnfinishedExtension.kt")
+            public void testUnfinishedExtension() throws Exception {
+                runTest("compiler/testData/psi/recovery/UnfinishedExtension.kt");
+            }
+
             @TestMetadata("ValNoName.kt")
             public void testValNoName() throws Exception {
                 runTest("compiler/testData/psi/recovery/ValNoName.kt");