RFR: 8238812: assert(false) failed: bad AD file

[Rahul Raghavan]

Request help to review this 8238812 fix.

<JBS> https://bugs.openjdk.java.net/browse/JDK-8238812

Found the root cause of the problem as that the following type 
two If checks are not folded into one for the sample test:

 170 ConI === 0 [[ 171 ]] #int:31
 171 CmpI === _ 144 170 [[ 172 179 ]]
 172 Bool === _ 171 [[ 173 ]] [ne]

 173 If === 158 172 [[ 176 177 ]]
 176 IfFalse === 173 [[ 168 ]] #0
 177 IfTrue === 173 [[ 180 ]] #1
 179 Bool === _ 171 [[ 180 ]] [lt]

 180 If === 177 179 [[ 181 182 ]]
 181 IfTrue === 180 [[ 168 ]] #1
 182 IfFalse === 180 [[ 218 ]] #0

Where 144 is the value and the ifs check for:
value != 31
value < 31

Now if we reach 182 IfFalse, the following holds:
   value != 31 && !(value < 31)
=> value != 31 && value >= 31
=> value > 31

But the type of value (144) becomes #int:16..31 :
 140 ConI === 0 [[ 141 ]] #int:2
 135 Phi === 534 481 528 [[ ... ]] #int:1..4 #tripcount
 141 LShiftI === _ 135 140 [[ 142 ]] #int:4..16
 143 ConI === 0 [[ 144 ]] #int:11
 142 AddI === _ 141 135 [[ 144 500 485 ]] #int:5..20
 144 AddI === _ 142 143 [[ ... ]] #int:16..31

And that means that value > 31 is always false and should be folded.
The root cause of the bug is that this does not happen.
Understood that the fix by Tobias for JDK-8236721 should optimize exactly above type cases
https://hg.openjdk.java.net/jdk/jdk/rev/9c53fdf6ba63

Found the IfNode::fold_compares optmization (and 8236721 related changes by Tobias)
is not called for 180-If, after the type of 144-AddI is set to #int:16..31.
because the _worklist is not correctly updated!

Proposed changes helped to add the required If node to _worklist (after the correct type setting of related value)
and with this change no failure due to existing fold_compares optimization happening later on.
Sample test passed and found no issues with various tier testing.

-------------

Commit messages:
 - 8238812: assert(false) failed: bad AD file

Changes: https://git.openjdk.java.net/jdk/pull/1563/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1563&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8238812
  Stats: 12 lines in 1 file changed: 12 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1563.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1563/head:pull/1563

PR: https://git.openjdk.java.net/jdk/pull/1563