Merge the precompiled classes containing structures that can't be produced by javac, add code with several line numbers per bytecode position, and remove the code for this in ClassWriterTest (it is safer to have a precompiled class than rebuilding it on the fly - the later approach cannot detect some bugs).

Warning: this class was not produced with an actual J2ME CLDC 1.1 toolchain, but with an ASM transform.

Small code quality improvements, hopefully the last ones for the core package.

See merge request asm/asm!77

Improve the code quality of Type and add more tests.

See merge request asm/asm!76

Improve the code quality of Label and add a Constants interface for internal constants

See merge request asm/asm!75

Update to be able to generate JDK 10 compatible classfile (54).

See merge request asm/asm!74

Also optimize the implementation with a new internal sort value, to avoid some String and StringBuilder manipulations.

In more details:
- add a Constants interface to avoid some magic constants in the code
- remove the INSTRUCTION_TYPES indirection in ClassReader, and use (table)switch statements on raw opcode values instead
- remove unnecessary flags BASIC_BLOCK_CHANGED, VISITED and VISITED2 in Label (replaced with a simpler algorithm using an EMPTY_LIST sentinel), as well as the redundant STORE flag
- add an otherLineNumbers field in Label to store line numbers in a cleaner way than with nextChangedBlock
- remove the inputStackTop field in Label, which was used to store different values depending on the compute options or basic block types. Replace it with new inputStackSize and outputStackSize fields in Label, and a new (private) outputStackStart field in Frame.
- use 'short' fields when possible in Frame and Label. Object size in memory with OpenJDK 1.8.0, measured with https://www.javaworld.com/article/2077496/testing-debugging/java-tip-130--do-you-know-your-data-size-.html, decreased from 64 to 56 bytes for Label (despite the added fields), and stayed unchanged (48 bytes) for Frame (despite the added field outputStackStart).
- split the large visitMaxs method in two smaller methods.
- performance is unchanged or improved: 1.02-1.04 speedup for ClassReader, no change for ClassReader+ClassWriter, 1.11 speedup for CR+CW with compute maxs, 1.05 speedup for CR+CW with compute frames.

There is no new feature, the number is just incremented so the
association between a JDK version and a classfile version is monotonic.

Improve the code quality of ClassReader.

See merge request !73

Improve the code quality of Frame.

See merge request !72

Improve the code quality of MethodWriter.

See merge request !71

Improve the code quality of ClassWriter.

See merge request !70

Also fix a bug in toByteArray() if(hasAsmInsns) ...: type annotations were not reset to null.