RFR: 8256486: Linux/Windows-x86 builds broken after JDK-8254231 [v4]

[Jorn Vernee]

> JDK-8254231 breaks the Linux and Windows x86 (32-bit) builds. This contains the needed changes to get it working again.
> 
> Perhaps the most interesting change is adding the `JNI_ENTRY_CPP_NOENV` macro. Using just JNI_ENTRY was causing a linkage failure, due to the declaration of the function in the class not having the same linkage specifiers. It looks like we can't just specify C linkage for class member functions.
> 
> However, in this case C linkage is not required, so I've added the new macro which doesn't have `extern "C"`. I've also dropped the `JNIEnv*` parameter, since it was not being used, but causing extra work for the caller.
> 
> Other than that, it's just about adding default definitions for missing functions, and moving around some code in MacroAssembler to be in the correct `#ifdef` blocks.
> 
> Testing: `make images` on Linux and Windows x86_32 platforms.

Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:

  Use the Unimplemented() macro instead of hlt()

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1266/files
  - new: https://git.openjdk.java.net/jdk/pull/1266/files/9dcbb58c..4f0c6ef9

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1266&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1266&range=02-03

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1266.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1266/head:pull/1266

PR: https://git.openjdk.java.net/jdk/pull/1266