dev-libs/stringifor: Use [[ ... ]] instead of POSIX [ ... ]

as per the coding style guide:
https://projects.gentoo.org/qa/policy-guide/ebuild-format.html#pg0101

change all instance of
[ "$e" != "./exe/stringifor_test_parse_large_csv" ] to
[[ "$e" != "./exe/stringifor_test_parse_large_csv" ]]

The changes were generated using these two commands:

```
find -name '*.ebuild' -exec sed -i -E \
's|(\s+)\[+(\s+)(\S+)(\s+)(\S+)(\s+)(\S+)(\s+)\]+(\s+)|\1\[\[\2\3\4\5\6\7\8\]\]\9|g' \
{} \+

find -name '*.ebuild' -exec sed -i -E \
's|\[(\s+)(\S+)(\s+)==?(\s+)(\S+)(\s+)\]|\[\1\2\3==\4\5\6\]|g' \
{} \+
```

this is aimed to be a series of commits meant to replace all instance of
POSIX [ ... ] to bash's [[ ... ]], to make guru up to date with the
coding style guide.

this process is divided up into a series of commits in order to make
review and testing more easy

Signed-off-by: ingenarel (NeoJesus) <ingenarel_neojesus@disroot.org>
Part-of: https://codeberg.org/gentoo/guru/pulls/6
Signed-off-by: Michał Górny <mgorny@gentoo.org>

dev-libs/stringifor/stringifor-1.1.4-r3.ebuild

@@ -74,7 +74,7 @@ src_compile() {
 src_test() {
 	${EPYTHON} FoBiS.py build -compiler custom -fc $(tc-getFC) ${BUILD_MODE_TESTS} || die
 	for e in $( find ./exe/ -type f -executable -print ); do
-		if [ "$e" != "./exe/stringifor_test_parse_large_csv" ] ; then
+		if [[ "$e" != "./exe/stringifor_test_parse_large_csv" ]] ; then
 			echo "  run test $e :" && { $e || die; }
 		else
 			# The output of this test is too huge so it's cutted here

dev-libs/stringifor/stringifor-1.1.8.ebuild

@@ -74,7 +74,7 @@ src_compile() {
 src_test() {
 	${EPYTHON} FoBiS.py build -compiler custom -fc $(tc-getFC) ${BUILD_MODE_TESTS} || die
 	for e in $( find ./exe/ -type f -executable -print ); do
-		if [ "$e" != "./exe/stringifor_test_parse_large_csv" ] ; then
+		if [[ "$e" != "./exe/stringifor_test_parse_large_csv" ]] ; then
 			echo "  run test $e :" && { $e || die; }
 		else
 			# The output of this test is too huge so it's cutted here