Merge branch 'jc/test-say-color-avoid-echo-escape' into maint

Merge branch 'jc/test-say-color-avoid-echo-escape' into maint

The "say" function in the test scaffolding incorrectly allowed
"echo" to interpret "\a" as if it were a C-string asking for a BEL
output.

* jc/test-say-color-avoid-echo-escape:
  test-lib: Fix say_color () not to interpret \a\b\c in the message