Return the correct location count for Matrices GetLocationCount() is currently returning the number of rows in the matrix, rather than the columns, which leads to shader validation errors (and test failures). This fix returns the number of columns in a matrix. Bug: angleproject:4200 Test: dEQP-GLES31.functional.separate_shader.random.63 Change-Id: I8d25eb3733c2ddbe53ff54794f480c1d43e22a88 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1952173 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com> Commit-Queue: Tim Van Patten <timvp@google.com>