RFR: JDK-8288824: [arm32] Display isetstate in register output

[Thomas Stuefe]

When analyzing [JDK-8288719](https://bugs.openjdk.org/browse/JDK-8288719), to know the current isetstate was useful. It would be nice if that were printed clearly in the register output to save some mental cycles parsing CPSR.

Looks like this:

Registers:
  r0  = 0x00000000
  r1  = 0xbe9e7fb8
  r2  = 0x00000000
  r3  = 0xb6f860ac
  r4  = 0xbe9e7fb8
  r5  = 0xb6f864e0
  r6  = 0xbe9e8060
  r7  = 0xbe9e7fb0
  r8  = 0xb6da8798
  r9  = 0x00000000
  r10 = 0x00000000
  fp  = 0x00000001
  r12 = 0xb6da87ec
  sp  = 0xbe9e7fb0
  lr  = 0xb6bc7dfb
  pc  = 0xb6bc7dfa
  cpsr = 0x800e0030
isetstate: Thumb

Registers:
  r0  = 0xb6be3664
  r1  = 0xbe947c70
  r2  = 0x00000058
  r3  = 0xb6f3e000
  r4  = 0xbe947c70
  r5  = 0xb6f3f510
  r6  = 0xb6c95bdc
  r7  = 0xbe947d18
  r8  = 0xbe947d98
  r9  = 0x00000000
  r10 = 0x00000000
  fp  = 0xbe947d14
  r12 = 0xb6c95f84
  sp  = 0xbe947c68
  lr  = 0xb6e97218
  pc  = 0xb6793f3c
  cpsr = 0x60000010
isetstate: ARM 


I refrained from parsing more information from the CPSR because I did not want to blow up the patch. ISETSTATE proved to be useful. More information can be added if needed.

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

Commit messages:
 - Display isetstate

Changes: https://git.openjdk.org/jdk/pull/9223/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9223&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8288824
  Stats: 14 lines in 1 file changed: 13 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/9223.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9223/head:pull/9223

PR: https://git.openjdk.org/jdk/pull/9223