Report relevant variable names in info logs on failed shader link

In case there's a variable precision mismatch or name conflict, the
variable name is now printed in the program info log to ease fixing the
issue in complex shaders. Also fixes a bug where multiple hashed names
would not all be converted to the original names in info logs by
preferring to match less characters in the regex, instead of preferring
to match more and possibly eating up all the hashed names except the
last.

BUG=332798
TEST=gpu_unittests, WebGL GLSL conformance tests

Review URL: https://codereview.chromium.org/132183002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244504 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244504