Daily improvements: parser port inference hardening

[mastertyko]

Summary

• support quoted values for --port and --inspect flags
• infer ports from URL-valued env vars and shell defaults
• infer ports from JVM -D*.port properties
• infer ports from URL/shell-default JVM port properties

Verification

• swift test --filter CommandParserTests
• swift test --filter CommandParserTests/testInferPortsFromEnvironmentAssignmentsWithURLShellDefaults
• swift test --filter CommandParserTests/testInferPortsFromEnvironmentAssignmentsWithURLValues
• swift test --filter CommandParserTests/testInferPortsFromJVMSystemProperties
• swift test --filter CommandParserTests/testInferPortsFromURLJVMSystemProperties
• swift test