[CLI] Introduce new compiler arguments for registering compiler plugins

With new syntax each plugin should be registered in separate argument with syntax
`-Xcompiler-plugin=classpath1,classpath2[=argument1=value1,argument2=value2]`

compiler/testData/cli/js/jsExtraHelp.out

@@ -93,6 +93,8 @@ where advanced options include:
   -Xphases-to-validate-after Validate backend state after these phases
   -Xphases-to-validate-before Validate backend state before these phases
   -Xplugin=<path>            Load plugins from the given classpath
+  -Xcompiler-plugin=<path1>,<path2>:<optionName>=<value>,<optionName>=<value>
+                             Register compiler plugin
   -Xprofile-phases           Profile backend phases
   -Xproper-ieee754-comparisons Generate proper IEEE 754 comparisons in all cases if values are statically known to be of primitive numeric types
   -Xread-deserialized-contracts Enable reading of contracts from metadata