fix: avoid skipping ordinary classes with $$Lambda in their names

[RynezzZ]

Summary

• require the synthetic class flag in addition to $$Lambda in the binary name
• add a real Instrumentation regression test for an ordinary Ordinary$$Lambda$1 class
• verify that a JVM-generated lambda is still skipped by the existing safeguard

Background

#1512 added a conservative safeguard because retransformation of generated lambdas can break applications on JDK 8. The current classification relies only on the binary name, however, and ordinary application classes are allowed to contain $$Lambda in that name. As a result, such classes are skipped by bytecode capture even though they are not JVM-generated lambdas.

This change does not remove or relax the protection for real generated lambdas. It only avoids classifying a non-synthetic ordinary class as a lambda based on its name alone.

Related: #1512, JDK-8145964

Testing

• JDK 17: mvnw.cmd -pl core test (264 tests, 0 failures, 0 errors, 7 skipped)
• JDK 8u131: mvnw.cmd -pl core -Dtest=InstrumentationUtilsTest surefire:test (2 tests, 0 failures, 0 errors)

[CLAassistant]

All committers have signed the CLA.