fix(logging): Summarize SKIPPED tests in debug.html.

Before: hundreds of SKIPPING lines in console.log.
After: A single summary line with a count.

Closes #1111
Why you remove print skipped test? ('SKIPPED testSuite description' [line 36](https://github.com/karma-runner/karma/pull/1115/files#diff-1271e14ba2b34ce3ce0c360df6187461R36))