Fix faster __vsc_escape_value

[hsfzxjy]

Fix #190255

The implementation of faster __vsc_escape_value provided by #190899 seems to misbehave on MacOS. After some investigation, the culprit happens to be of two fold:

1. Different from the Linux version, the od on Mac will print out sequence of spaces at the beginning of each line, causing the previous implementation to produce dangling \x\x\x and further slow down the bash parsing;
2. Even after the first problem fixed, the od+tr solution on Mac is still much slower than on Linux, when input content size comes to around 6000 (around 12s according to CI testing), due to unknown reason.

Considering both of these, I decide to ditch the od+tr version, and keep only the one with pure bash.

[Tyriar]

Thanks for the follow up!