Make ConvertFrom-Json deserialize an array of objects with multiple lines. (#3823)

* Fixing ConvertFrom-Json on CoreCLR to be able to handle a collection of strings which represent a JSON content.

* Adding test case for ConvertFrom-Json to process an array of PSObjects as a single string.

test/powershell/Modules/Microsoft.PowerShell.Utility/Pester.Commands.Cmdlets.Json.Tests.ps1

@@ -228,7 +228,6 @@ Describe "Json Tests" -Tags "Feature" {
 
             # add a ScriptProperty called IsOld which returns whether the version is an older version
             $versionObject | Add-Member -MemberType ScriptProperty -Name IsOld -Value { ($this.Major -le 3) }
-
             $jstr = ConvertTo-Json $versionObject
 
             # convert the JSON string to a JSON object
@@ -1455,4 +1454,25 @@ Describe "Json Bug fixes"  -Tags "Feature" {
     {
         RunJsonTest $testCase
     }
+
+    It "ConvertFrom-Json deserializes an array of PSObjects (in multiple lines) as a single string." {
+
+        # Create an array of PSCustomObjects, and serialize it
+        $array = [pscustomobject]@{ objectName = "object1Name"; objectValue = "object1Value" },
+                 [pscustomobject]@{ objectName = "object2Name"; objectValue = "object2Value" }
+
+        # Serialize the array to a text file
+        $filePath = Join-Path $TESTDRIVE test.json
+        $array | ConvertTo-Json | Out-File $filePath -Encoding utf8
+
+        # Read the object as an array of PSObjects and deserialize it.
+        $result = Get-Content $filePath | ConvertFrom-Json
+        $result.Count | Should be 2
+    }
+
+    It "ConvertFrom-Json deserializes an array of strings (in multiple lines) as a single string." {
+
+        $result = "[1,","2,","3]" | ConvertFrom-Json
+        $result.Count | Should be 3
+    }
 }