ZJIT: Edit testing sections in zjit.md

Running just one file under test/ is not running all tests.

Author: XrXr

doc/jit/zjit.md

@@ -287,28 +287,28 @@ cd zjit && cargo insta review
 
 Test changes will be reviewed alongside code changes.
 
-### Running integration tests
+### Running smoke tests
 
-This command runs Ruby execution tests.
-
-```bash
-make test-all TESTS="test/ruby/test_zjit_cli.rb"
-```
-
-You can also run a single test case by matching the method name:
+Runs both `make zjit-test` and `test/ruby/test_zjit_cli.rb`:
 
 ```bash
-make test-all TESTS="test/ruby/test_zjit_cli.rb -n TestZJITCLI#test_enabled"
+make zjit-check
 ```
 
-### Running all tests
+### Integration testing
 
-Runs both `make zjit-test` and `test/ruby/test_zjit_cli.rb`:
+A thorough test run will want to enable ZJIT on Ruby workloads. Some
+test suites written in Ruby in this repository accepts the `RUN_OPTS`
+Make macro for passing ruby(1) command-line arguments:
 
 ```bash
-make zjit-check
+make test-all RUN_OPTS='--zjit-call-threshold=2'
+make btest RUN_OPTS='--zjit-call-threshold=1'
 ```
 
+See [Testing Ruby](rdoc-ref:contributing/testing_ruby.md) for a list of
+test suites.
+
 ## Statistics Collection
 
 ZJIT provides detailed statistics about JIT compilation and execution behavior.