Implement a detached or nested body (enclosed by curly braces)

Problem/Motivation

Implement a detached or nested body (enclosed by curly braces). PHP allows statements to be surrounded by curly braces (independent of or nested within a block statement). Such practice seems unusual and more likely to be a typo. Nonetheless, it is allowed, a "bug" was filed regarding same, and we will support it.

Proposed resolution

See patch(es).

Remaining tasks

Before committing, code will be reviewed, tested against D8 core files, and documentation updated.

User interface changes

Not applicable.

API changes

To be completed later.