Fix an NPE in VirtualFileKotlinClassFinder#findKotlinClass(JavaClass)

Happens for nonphysical PsiClass
Fix error message
Extracted test for "Join Lines" from CodeTransformationsTest.
Simplified CodeTransformationTest. Only one doTest method remains, intention class is moved to test data. Merged other intention tests (SpecifyTypeExplicitlyTest, ConvertToBlock/ExpressionBodyTest) into this one.
Renamed CodeTransformationTest -> IntentionTest.
KT-5397 Simplify text of DeMorgan law conversion intentions

 #KT-5397
Added test for KT-4827 UOE at PackageType.throwException()

 #KT-4827 obsolete
 #EA-53605 obsolete
KT-4980 'Remove braces' intention throws NPE for a for-loop with variable declaration

 #KT-4980 fixed
Minor. Renamed test data to avoid repetitions.
Optimized KotlinBuilder for targets without Kotlin. Checking dirty/removed files only.
Made it possible to run incremental compiler from IDEA.

Two guava functions used were replaced with custom tiny functions, because JPS plugin won't have guava in classpath.
Got rid of ModuleDescription intermediate entity.
Not writing compiler arguments from JPS plugin by default.
Not writing compiler script path when in JPS plugin output.

XML script is removed after JPS plugin session anyway, so it's usually hard to check its contents. Also, it is redundant since -printArgs will write it anyway, so there is still possibility to debug.
Moved current incremental compiler test data into subdirectory.

Tweaked test generator to avoid creating test methods for parent directory of tests.
Add test for failing assertion in JetPropertyStub.createStub

Test for eec6fbb205abb90b590a8936f8a9d328713f4348
Delayed because test data was causing reindex of the whole project
Builtins: made Unit object.
JVM backend: fixed the getting Unit instance -- Unit.VALUE -> Unit.instance$.
Minor: fixed tests.
Minor in IDEA plugin: jet -> kotlin in JetBundle.properties