strings: add a test case of growLen is negative
Before committing, the test coverage of strings/builder.go is 97.4%
After committing, the test coverage of strings/builder.go is 100%
Change-Id: I22643b1c4632b5ca7ef98362f32bb85faae80bad
GitHub-Last-Rev:
2a55ca3e33d3aabd2ccc047de580abcfe05d6bb4
GitHub-Pull-Request: golang/go#55004
Reviewed-on: https://go-review.googlesource.com/c/go/+/430156
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Jenny Rakoczy <jenny@golang.org>