Add a new parameter to JpegImage.getData to indicate the source of the image data (issue 9513)

The purpose of this patch is to provide a better default behaviour when `JpegImage` is used to parse standalone JPEG images with CMYK colour spaces.
Since the issue that the patch concerns is somewhat of a special-case, the implementation utilizes the already existing decode support in an attempt to minimize the impact w.r.t. code size.

*Please note:* It's always possible for the user of `JpegImage` to control image inversion, and thus override the new behaviour, by simply passing a custom `decodeTransform` array upon initialization.

src/core/jpeg_stream.js

@@ -97,8 +97,12 @@ let JpegStream = (function JpegStreamClosure() {
     const jpegImage = new JpegImage(jpegOptions);
 
     jpegImage.parse(this.bytes);
-    let data = jpegImage.getData(this.drawWidth, this.drawHeight,
-                                 this.forceRGB);
+    let data = jpegImage.getData({
+      width: this.drawWidth,
+      height: this.drawHeight,
+      forceRGB: this.forceRGB,
+      isSourcePDF: true,
+    });
     this.buffer = data;
     this.bufferLength = data.length;
     this.eof = true;