gl: print shader sources one line at a time

This ensures they don't get truncated by the ADB log.

Bug: skia:
Change-Id: I5ad0222e54f667c0dd3a5b1174d43588d90ca231
Reviewed-on: https://skia-review.googlesource.com/24421
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
1 file changed