RFR: 8270086: ARM32-softfp: Do not load CONSTANT_double using the condy helper methods in the interpreter

[Christoph Göttschkes]

Hi,

please review this fix for the template interpreter for ARM32-softfp.

With the introduction of condy, the interpreter started to load double constants using the condy_helper, which is unnecessary. Also, the [resolve_ldc](https://github.com/openjdk/jdk/blob/8973867fb9568a3a527b763c9ce10cebdfb306d0/src/hotspot/share/interpreter/interpreterRuntime.cpp#L148) implementation of the interpreter runtime might not be designed to load constant values. It should only load strings and condy.

https://github.com/openjdk/jdk/blob/2ee56fd1cf4acd634e19cc77b7c9a6858e1c315a/src/hotspot/cpu/arm/templateTable_arm.cpp#L515-L560

I refactored the ldc2_w bytecode imlpementation. Now, the ifdef between soft and hard float covers both types, CONSTANT_Long and CONSTANT_Double. I did this, because for the softfp, we can use a conditional cmp, since double and long are both placed on the stack in the same way. The same is also done for CONSTANT_Integer and CONSTANT_Float in the ldc bytecode implementation. Also, I think it is easier to follow the code this way.

Old ldc2_w implementation (before condy was implemented for ARM32):

https://github.com/openjdk/jdk/blob/7101b28dc3903be27cb46a00781f4d74f81f1114/src/hotspot/cpu/arm/templateTable_arm.cpp#L497-L537

Testing: ARMv7-A (hardfp) hotspot tier1, ARMv5TE (softfp) hotspot tier1

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Commit messages:
 - 8270086: ARM32-softfp: Do not load CONSTANT_double using the condy helper methods in the interpreter

Changes: https://git.openjdk.java.net/jdk/pull/4767/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4767&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8270086
  Stats: 15 lines in 1 file changed: 12 ins; 3 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4767.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4767/head:pull/4767

PR: https://git.openjdk.java.net/jdk/pull/4767