Fix operator_identifier
Problem
1. Currently `//` ends up matching `operator_identier`
2. There's also a bug in regex.
Solution
1. Implement a workaround to avoid `//`.
2. Escape `-`, copying from the identifier regex.
SCALA_SCALA_LIBRARY_EXPECTED=100
SCALA_SCALA_COMPILER_EXPECTED=66
-DOTTY_COMPILER_EXPECTED=74
+DOTTY_COMPILER_EXPECTED=66
if [ ! -d "$SCALA_SCALA_DIR" ]; then
echo "\$SCALA_SCALA_DIR must be set"
