Addressing code review comments

Author: MSLaguana

lib/Runtime/Library/JavascriptExceptionMetadata.cpp

@@ -95,10 +95,10 @@ namespace Js {
 
         LPCUTF8 functionSource = sourceInfo->GetSource(_u("Jsrt::JsExperimentalGetAndClearExceptionWithMetadata"));
 
-        charcount_t startByteOffset;
-        charcount_t endByteOffset;
-        charcount_t startCharOffset;
-        charcount_t endCharOffset;
+        charcount_t startByteOffset = 0;
+        charcount_t endByteOffset = 0;
+        charcount_t startCharOffset = 0;
+        charcount_t endCharOffset = 0;
 
 
         startCharOffset = cache->GetCharacterOffsetForLine(line, &startByteOffset);
@@ -143,7 +143,7 @@ namespace Js {
                 }
                 else
                 {
-                    // This should not be possible
+                    AssertMsg(FALSE, "Line ending logic out of sync between Js::JavascriptExceptionMetadata and JsUtil::LineOffsetCache::GetCharacterOffsetForLine");
                     return false;
                 }
             }