Fix new String(new Char[0])

Author: mortezag

CLR/Libraries/CorLib/corlib_native_System_String.cpp

@@ -548,7 +548,7 @@ HRESULT Library_corlib_native_System_String::FromCharArray( CLR_RT_StackFrame& s
     CLR_UINT32              len;
 
     array = stack.Arg1().DereferenceArray(); if(!array) TINYCLR_SET_AND_LEAVE(S_OK);
-    len   = array->m_numOfElements         ; if(!len  ) TINYCLR_SET_AND_LEAVE(S_OK);
+    len   = array->m_numOfElements         ;
 
     if(length == -1) length = len - startIndex;
 

Test/Platform/Tests/CLR/mscorlib/systemlib/systemlib2/SystemStringTests.cs

@@ -57,8 +57,12 @@ public MFTestResults Ctor_Test()
             char[] car2 = new char[] { (char)0, (char)65};
             string s = new string(car2);
             testResult &= (s == "\0A");
-                
             Log.Comment("This was previously bug 20620");
+
+            Log.Comment("new char[0]");
+            str = new string(new char[0]);
+            testResult &= (str == string.Empty);
+
             return (testResult ? MFTestResults.Pass : MFTestResults.Fail);
         }
         [TestMethod]