Had to edit some bytecodeText tests to account for the fact that JVM_IR
no longer generates explicit initializations for ConstantValue fields,
but NoConstantValueAttributeForNonConstVals is not the default yet.
For comparison intrinsics and for instanceof checks, make
it possible to get the the stack value produced and branch
on that directly instead of materializing a boolean to
branch on from it.
That reduces code such as
```
IF_CMPEQ L1
CONST_0
GOTO L2
L1: CONST_1
L2: IFEQ L3
```
to just one IF_CMP instruction.
Introduce lowering to remove null checks for primitive type
expressions and replace them with true/false. Side-effects
are preserved.
Generate ifnull/ifnonnull instructions for null checks instead
of materializing a null literal for an equality check.
- Turn some const conditions into non-const conditions
- Make sure inlined const values are used where required
(otherwise they are eliminated by POP backward propagation)
