This patch adds missing newlines, trims multiple redundant final
newlines into a single one, and trims redundant leading newlines in all
*.phpt sections.

According to POSIX, a line is a sequence of zero or more non-' <newline>'
characters plus a terminating '<newline>' character. [1] Files should
normally have at least one final newline character.

C89 [2] and later standards [3] mention a final newline:
"A source file that is not empty shall end in a new-line character,
which shall not be immediately preceded by a backslash character."

Although it is not mandatory for all files to have a final newline
fixed, a more consistent and homogeneous approach brings less of commit
differences issues and a better development experience in certain text
editors and IDEs.

[1] http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_206
[2] https://port70.net/~nsz/c/c89/c89-draft.html#2.1.1.2
[3] https://port70.net/~nsz/c/c99/n1256.html#5.1.1.2

Instead of directly writing to stdout. This allows doing a print_r
into a string, without using output buffering.

The motivation for this is bug #67467: print_r() in return mode
will still dump the string to stdout (causing a potential information
leak) if a fatal error occurs.

of course we can try to refactor the current flow to make this error can
be catched safly.

but as 7.0.0 is releasing,  I don't think a refactor is safe now. and
actually I don't see any gain to make this catchable.

so let's keep this be consistent with 5.6 and safe for now