Adjust test-dyno Makefile to allow parallel on macOS (chapel-lang#2…

…6030)

Adjust the Dyno tests Makefile target to correctly use concurrency (as
specified in `make` invocation) on macOS.

The problem was due to different syntax for capture groups and "or" on
macOS `sed`. Fixed by adjusting the `sed` invocation to work on either
macOS or GNU sed.

Getting a parallel run working also requires using GNU Make 4.x, which
isn't the default on macOS -- see [backing
issue](Cray/chapel-private#6770).

[reviewed by @DanilaFe , thanks!]

Resolves Cray/chapel-private#6770.

Testing:
- [x] `make -jN test-dyno` on my mac
- [x] `make -jN test-dyno` on chapdl
- [x] paratest cuz changing Makefiles is scary

compiler/Makefile

@@ -182,7 +182,7 @@ frontend-shared: FORCE $(CHPL_CONFIG_CHECK) $(COMPILER_BUILD)
 
 test-frontend: FORCE frontend-tests $(CHPL_CONFIG_CHECK) $(COMPILER_BUILD)
 	@echo "Running the frontend tests..."
-	JOBSFLAG=`echo "$$MAKEFLAGS" | sed -n 's/.*\(-j\|--jobs=\) *\([0-9][0-9]*\).*/-j\2/p'` ; \
+	JOBSFLAG=`echo "$$MAKEFLAGS" | sed -n -E 's/.*(-j|--jobs=) *([0-9][0-9]*).*/-j\2/p'` ; \
 	  cd $(COMPILER_BUILD)/frontend/test && ctest $$JOBSFLAG . ;
 
 frontend-tests: $(CHPL_CONFIG_CHECK) $(COMPILER_BUILD)